[Federal Register Volume 81, Number 168 (Tuesday, August 30, 2016)]
[Proposed Rules]
[Pages 59736-59798]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-20097]



[[Page 59735]]

Vol. 81

Tuesday,

No. 168

August 30, 2016

Part II





Department of Energy





-----------------------------------------------------------------------





10 CFR Parts 429, 430, and 431





Energy Conservation Program for Consumer Products and Certain 
Commercial and Industrial Equipment: Test Procedures for Consumer and 
Commercial Water Heaters; Proposed Rule

  Federal Register / Vol. 81 , No. 168 / Tuesday, August 30, 2016 / 
Proposed Rules  

[[Page 59736]]


-----------------------------------------------------------------------

DEPARTMENT OF ENERGY

10 CFR Parts 429, 430, and 431

[Docket No. EERE-2015-BT-TP-0007]
RIN 1904-AC91


Energy Conservation Program for Consumer Products and Certain 
Commercial and Industrial Equipment: Test Procedures for Consumer and 
Commercial Water Heaters

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Supplemental notice of proposed rulemaking.

-----------------------------------------------------------------------

SUMMARY: The U.S. Department of Energy (DOE) proposes to establish a 
mathematical conversion factor to translate the current energy 
conservation standards and the measured values determined under the 
energy factor, thermal efficiency, and standby loss test procedures for 
consumer water heaters and certain commercial water heaters to those 
determined under the more recently adopted uniform energy factor test 
procedure. As required by the Energy Policy and Conservation Act of 
1975 (EPCA), as amended, DOE initially presented proposals for 
establishing a mathematical conversion factor in a notice of proposed 
rulemaking (NOPR) published on April 14, 2015 (April 2015 NOPR). Upon 
further analysis and review of the public comments received in response 
to the April 2015 NOPR, DOE is publishing this supplemental notice of 
proposed rulemaking (SNOPR), which: updates the proposed mathematical 
conversion factors based on new test data received after the 
publication of the April 2015 NOPR; proposes updates to the methodology 
for developing the conversions for certain covered water heaters based 
on feedback received from interested parties; and proposes a new 
approach for denominating the existing energy conservation standards in 
terms of the new uniform energy factor (UEF) metric.

DATES: Comments: DOE will accept comments, data, and information 
regarding this SNOPR submitted no later than September 29, 2016. See 
section V, ``Public Participation,'' for details.

ADDRESSES: All comments submitted must identify the SNOPR for Test 
Procedures for the Conversion Factor for Consumer and Certain 
Commercial Water Heaters, and provide docket number EERE-2015-BT-TP-
0007 and/or regulatory information number (RIN) 1904-AC91. Comments may 
be submitted using any of the following methods:
    1. Federal eRulemaking Portal: www.regulations.gov. Follow the 
instructions for submitting comments.
    2. Email: [email protected]. Include the 
docket number and/or RIN in the subject line of the message. Submit 
electronic comments in WordPerfect, Microsoft Word, PDF, or ASCII file 
format, and avoid the use of special characters or any form of 
encryption.
    3. Postal Mail: Ms. Ashley Armstrong, U.S. Department of Energy, 
Building Technologies Office, Mailstop EE-5B, 1000 Independence Avenue 
SW., Washington, DC 20585-0121. If possible, please submit all items on 
a compact disc (CD), in which case it is not necessary to include 
printed copies.
    4. Hand Delivery/Courier: Ms. Ashley Armstrong, U.S. Department of 
Energy, Building Technologies Office, 950 L'Enfant Plaza SW., Room 
6094, Washington, DC 20024. Telephone: (202) 586-2945. If possible, 
please submit all items on a CD, in which case it is not necessary to 
include printed copies.
    No telefacsimilies (faxes) will be accepted. For detailed 
instructions on submitting comments and additional information on the 
rulemaking process, see section V of this document (Public 
Participation).
    Docket: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts, comments, and other supporting 
documents/materials, is available for review at www.regulations.gov. 
All documents in the docket are listed in the www.regulations.gov 
index. However, not all documents listed in the index may be publicly 
available, such as those containing information that is exempt from 
public disclosure.
    A link to the docket Web page can be found at: https://www.regulations.gov/docket?D=EERE-2015-BT-TP-0007. This Web page 
contains a link to the docket for this notice on the 
www.regulations.gov site. The www.regulations.gov Web page contains 
simple instructions on how to access all documents, including public 
comments, in the docket. See section V, ``Public Participation,'' for 
information on how to submit comments through www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Ms. Ashley Armstrong, U.S. Department 
of Energy, Office of Energy Efficiency and Renewable Energy, Building 
Technologies Office, EE-5B, 1000 Independence Avenue SW., Washington, 
DC, 20585-0121. Telephone: (202) 586-6590. Email: 
[email protected].
    Mr. Eric Stas, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW., Washington, DC, 20585-
0121. Telephone: (202) 586-9507. Email: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Authority and Background
II. Summary of the Supplemental Notice of Proposed Rulemaking
III. Discussion
    A. Purpose
    B. Scope
    C. Approaches for Developing Conversions
    1. Overview of Analytical Methods Approach
    2. Overview of Empirical Regression Approach
    3. Overview of Hybrid Approach
    4. Analytical Methods Approach
    a. Maximum GPM
    b. First-Hour Rating
    c. Uniform Energy Factor
    i. Consumer Storage Water Heaters
    ii. Consumer Instantaneous Water Heater
    iii. Residential-Duty Commercial Storage Water Heaters
    iv. Residential-Duty Commercial Electric Instantaneous Water 
Heaters
    5. Empirical Regression Approach
    D. Testing Conducted for the Mathematical Conversion
    1. Repeatability
    E. Testing Results and Analysis of Test Data
    1. Impact of Certain Water Heater Attributes on Efficiency 
Ratings
    2. Conversion Factor Derivation
    a. Consumer Storage Water Heaters
    i. Test Results
    ii. Conversion Factor Results
    b. Consumer Instantaneous Water Heaters
    i. Test Results
    ii. Conversion Factor Results
    c. Residential-Duty Commercial Storage Water Heaters
    i. Test Results
    ii. Conversion Factor Results
    d. Residential-Duty Commercial Instantaneous Water Heaters
    e. Grid-Enabled Storage Water Heaters
    3. Energy Conservation Standard Derivation
    a. Storage Volume Used for Calculations
    F. Compliance and Grandfathering
    G. Certification
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Order 12866
    B. Review Under the Regulatory Flexibility Act
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999

[[Page 59737]]

    I. Review Under Executive Order 12630
    J. Review Under Treasury and General Government Appropriations 
Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
V. Public Participation
    A. Submission of Comments
    B. Issues on Which DOE Seeks Comment
VI. Approval of the Office of the Secretary

I. Authority and Background

    Title III Part B \1\ of the Energy Policy and Conservation Act of 
1975 (``EPCA'' or, ``the Act''), Public Law 94-163 (42 U.S.C. 6291-
6309, as codified) sets forth a variety of provisions designed to 
improve energy efficiency and established the Energy Conservation 
Program for Consumer Products Other Than Automobiles.\2\ These include 
consumer water heaters, one subject of this document. (42 U.S.C. 
6292(a)(4)) Title III, Part C \3\ of EPCA, Public Law 94-163 (42 U.S.C. 
6311-6317, as codified), added by Public Law 95-619, Title IV, Sec. 
441(a), established the Energy Conservation Program for Certain 
Industrial Equipment, which includes the commercial water heating 
equipment that is another subject of this rulemaking. (42 U.S.C. 
6311(1)(K))
---------------------------------------------------------------------------

    \1\ For editorial reasons, upon codification in the U.S. Code, 
Part B was redesignated Part A.
    \2\ All references to EPCA in this document refer to the statute 
as amended through the Energy Efficiency Improvement Act of 2015 
(EEIA 2015), Public Law 114-11 (April 30, 2015).
    \3\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
---------------------------------------------------------------------------

    Under EPCA, DOE's energy conservation program generally consists of 
four parts: (1) Testing; (2) labeling; (3) energy conservation 
standards; and (4) certification and enforcement procedures. The 
testing requirements consist of test procedures that manufacturers of 
covered products and equipment must use as the basis for certifying to 
DOE that their products and equipment comply with the applicable energy 
conservation standards adopted under EPCA, and for making other 
representations about the efficiency of those products. (42 U.S.C. 
6293(c); 42 U.S.C. 6295(s); 42 U.S.C. 6314) Similarly, DOE must use 
these test procedures to determine whether such products and certain 
equipment comply with any relevant standards promulgated under EPCA. 
(42 U.S.C. 6295(s); 42 U.S.C. 6314)
    EPCA contains what is known as an ``anti-backsliding'' provision, 
which prevents the Secretary from prescribing any amended standard that 
either increases the maximum allowable energy use or decreases the 
minimum required energy efficiency of a covered product. (42 U.S.C. 
6295(o)(1); 6313(a)(6)(B)(iii)(I)) Also, the Secretary may not 
prescribe an amended or new standard if interested persons have 
established by a preponderance of the evidence that the standard is 
likely to result in the unavailability in the United States of any 
covered product type (or class) of performance characteristics 
(including reliability), features, sizes, capacities, and volumes that 
are substantially the same as those generally available in the United 
States. (42 U.S.C. 6295(o)(4); 6313(a)(6)(B)(iii)(II))
    EPCA prescribed the energy conservation standards for consumer 
water heaters, shown in Table I.1 (42 U.S.C. 6295(e)(1)), and directed 
DOE to conduct further rulemakings to determine whether to amend these 
standards (42 U.S.C. 6295(e)(4)(A)-(B)) DOE notes that under 42 U.S.C. 
6295(m), the agency must periodically review its already established 
energy conservation standards for a covered product. Under this 
requirement, the next review that DOE would need to conduct must occur 
no later than six years from the issuance of a final rule establishing 
or amending a standard for a covered product.

Table I.1--EPCA Initial Energy Conservation Standards for Consumer Water
                                 Heaters
------------------------------------------------------------------------
            Product class                        Energy factor
------------------------------------------------------------------------
Gas Water Heater.....................  0.62 - (0.0019 x Rated Storage
                                        Volume in gallons).
Oil Water Heater.....................  0.59 - (0.0019 x Rated Storage
                                        Volume in gallons).
Electric Water Heater................  0.95 - (0.00132 x Rated Storage
                                        Volume in gallons).
------------------------------------------------------------------------

    On October 17, 1990, DOE published a final rule which updated the 
test procedure from a no-draw test to a six-draw, 24-hour simulated-use 
test. 55 FR 42162. The effect of this change in test procedure was 
investigated on a sample of representative units and based on the 
results of testing on those units, DOE updated the energy conservation 
standard for electric water heaters to reflect the new test procedure. 
To account for the change in test procedure for electric water heaters, 
DOE amended the standard to 0.93-(0.00132 x Rated Storage Volume). Id. 
at 42177. DOE notes that these statutory energy conservation standards 
apply to both storage and instantaneous consumer water heaters 
regardless of volume capacity.
    On April 16, 2010, DOE published a final rule (hereinafter referred 
to as the ``April 2010 final rule'') that amended the energy 
conservation standards for specified classes of consumer water heaters, 
and maintained the existing energy conservation standards for tabletop 
and electric instantaneous water heaters. 75 FR 20112. The standards 
adopted by the April 2010 final rule are shown below in Table I.2. 
These standards apply to all water heater product classes listed in 
Table I.2 and manufactured in, or imported into, the United States on 
or after April 16, 2015, for all classes except for tabletop and 
electric instantaneous. For these latter two classes, compliance with 
these standards has been required since April 15, 1991. 55 FR 42162 
(Oct. 17, 1990). Current energy conservation standards for consumer 
water heaters can be found in DOE's regulations at 10 CFR 430.32(d).

 Table I.2--DOE Energy Conservation Standards for Consumer Water Heaters
------------------------------------------------------------------------
                                     Rated storage
          Product class               volume ***       Energy factor **
------------------------------------------------------------------------
Gas-fired Storage...............  >=20 gal and <=55   0.675 - (0.0015 x
                                   gal.                Vs).
                                  >55 gal and <=100   0.8012 - (0.00078
                                   gal.                x Vs).
Oil-fired Storage...............  <=50 gal..........  0.68 - (0.0019 x
                                                       Vs).
Electric Storage................  >=20 gal and <=55   0.96 - (0.0003 x
                                   gal.                Vs).

[[Page 59738]]

 
                                  >55 gal and <=120   2.057 - (0.00113 x
                                   gal.                Vs).
Tabletop*.......................  >=20 gal and <=120  0.93 - (0.00132 x
                                   gal.                Vs).
Gas-fired Instantaneous.........  <2 gal............  0.82 - (0.0019 x
                                                       Vs).
Electric Instantaneous *........  <2 gal............  0.93 - (0.00132 x
                                                       Vs).
------------------------------------------------------------------------
* Tabletop and electric instantaneous water heater standards were not
  updated by the April 2010 final rule.
** Vs is the ``Rated Storage Volume'' which equals the water storage
  capacity of a water heater (in gallons), as specified by the
  manufacturer.
*** Rated Storage Volume limitations result from either a lack of test
  procedure coverage or from divisions created by DOE when adopting
  standards. The division at 55 gallons for gas-fired and electric
  storage water heaters was established in the April 16, 2010 final rule
  amending energy conservation standards. 75 FR 20112. The other storage
  volume limitations shown in this table are a result of test procedure
  applicability and are discussed in the July 2014 final rule. 79 FR
  40542 (July 11, 2014).

    Water heaters that use gas, oil, electricity, or a combination of 
these fuels, that are not within the rated storage volume sizes stated 
in Table I.2 (e.g., gas-fired storage less than 20 gallons or greater 
than 100 gallons), are subject to the applicable energy conservation 
standard established in EPCA.
    The initial Federal energy conservation standards and test 
procedures for commercial water heating equipment were added to EPCA as 
an amendment made by the Energy Policy Act of 1992 (EPACT). (42 U.S.C. 
6313(a)(5)) These initial energy conservation standards corresponded to 
the efficiency levels contained in the American Society of Heating, 
Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1 
(ASHRAE Standard 90.1) in effect on October 24, 1992. The statute 
provided that if the efficiency levels in ASHRAE Standard 90.1 were 
amended after October 24, 1992, the Secretary must establish an amended 
uniform national standard at new minimum levels for each equipment type 
specified in ASHRAE Standard 90.1, unless DOE determines, through a 
rulemaking supported by clear and convincing evidence, that national 
standards more stringent than the new minimum levels would result in 
significant additional energy savings and be technologically feasible 
and economically justified. (42 U.S.C. 6313(a)(6)(A)(ii)(I)-(II)) The 
statute was subsequently amended to require DOE to review its standards 
for commercial water heaters (and other ``ASHRAE equipment'') every six 
years. (42 U.S.C. 6313(a)(6)(C)) On January 12, 2001, DOE published a 
final rule for commercial water heating equipment that amended energy 
conservation standards by adopting the levels in ASHRAE Standard 90.1-
1999 for all types of commercial water heating equipment, except for 
electric storage water heaters. 66 FR 3336. For electric storage water 
heaters, the standard in ASHRAE Standard 90.1-1999 was less stringent 
than the standard prescribed in EPCA and, consequently, would have 
increased energy consumption, so DOE maintained the standards for 
electric storage water heaters at the statutorily prescribed level. DOE 
published the most recent final rule for commercial water heating 
equipment on July 17, 2015, in which DOE adopted the thermal efficiency 
level for oil-fired storage water heaters that was included in ASHRAE 
90.1-2013. 80 FR 42614. The current standards for commercial water 
heating equipment are presented in Table I.3.

                 Table I.3--Energy Conservation Standards for Commercial Water Heating Equipment
----------------------------------------------------------------------------------------------------------------
                                                                         Energy conservation standards*
                                                              --------------------------------------------------
                                                                   Minimum thermal
         Equipment category                     Size            efficiency (equipment     Maximum standby loss
                                                                 manufactured on and     (equipment manufactured
                                                                after October 9, 2015)  on and after October 29,
                                                                   ** [dagger] (%)      2003)** [dagger][dagger]
----------------------------------------------------------------------------------------------------------------
Electric storage water heaters......  All....................                      N/A  0.30 + 27/Vm(%/h).
Gas-fired storage water heaters.....  <=155,000 Btu/h........                       80  Q/800 + 110(Vr)1/2 (Btu/
                                                                                         h).
                                      >155,000 Btu/h.........                       80  Q/800 + 110(Vr)1/2 (Btu/
                                                                                         h).
Oil-fired storage water heaters.....  <=155,000 Btu/h........               80[dagger]  Q/800 + 110(Vr)1/2 (Btu/
                                                                                         h).
                                      >155,000 Btu/h.........               80[dagger]  Q/800 + 110(Vr)1/2 (Btu/
                                                                                         h).
Electric instantaneous water          <10 gal................                       80  N/A.
 heaters[dagger][dagger][dagger].
                                      >=10 gal...............                       77  2.30 + 67/Vm (%/h).
Gas-fired instantaneous water         <10 gal................                       80  N/A.
 heaters and hot water supply
 boilers.
                                      >=10 gal...............                       80  Q/800 + 110(Vr)1/2 (Btu/
                                                                                         h).
Oil-fired instantaneous water heater  <10 gal................                       80  N/A.
 and hot water supply boilers.
                                      >=10 gal...............                       78  Q/800 + 110(Vr)1/2 (Btu/
                                                                                         h)
----------------------------------------------------------------------------------------------------------------
         Equipment Category                     Size                       Minimum thermal insulation
----------------------------------------------------------------------------------------------------------------
Unfired hot water storage tank......  All....................                       R-12.5.
----------------------------------------------------------------------------------------------------------------
* Vm is the measured storage volume, and Vr is the rated volume, both in gallons. Q is the nameplate input rate
  in Btu/h.
** For hot water supply boilers with a capacity of less than 10 gallons: (1) The standards are mandatory for
  units manufactured on and after October 21, 2005 and (2) units manufactured on or after October 23, 2003, but
  prior to October 21, 2005, must meet either the standards listed in this table or the applicable standards in
  Subpart E of this Part for a ``commercial packaged boiler.''
[dagger] For oil-fired storage water heaters: (1) The standards are mandatory for equipment manufactured on and
  after October 9, 2015, and (2) equipment manufactured prior to that date must meet a minimum thermal
  efficiency level of 78 percent.

[[Page 59739]]

 
[dagger][dagger] Water heaters and hot water supply boilers having more than 140 gallons of storage capacity
  need not meet the standby loss requirement if: (1) The tank surface area is thermally insulated to R-12.5 or
  more, (2) a standing pilot light is not used, and (3) for gas-fired or oil-fired storage water heaters, they
  have a fire damper or fan-assisted combustion.
[dagger][dagger][dagger] Energy conservation standards for electric instantaneous water heaters are included in
  EPCA. (42 U.S.C. 6313(a)(5)(D)-(E)) The compliance date for these energy conservation standards is January 1,
  1994. In a NOPR for energy conservation standards for commercial water heating equipment published on May 31,
  2016, DOE proposed to codify these standards for electric instantaneous water heaters in its regulations at 10
  CFR 431.110. 81 FR 34440.

    On December 18, 2012, the American Energy Manufacturing Technical 
Corrections Act (AEMTCA), Public Law 112-210, was signed into law. In 
relevant part, it amended EPCA to require that DOE publish a final rule 
establishing a uniform efficiency descriptor and accompanying test 
methods for consumer water heaters and certain commercial water heating 
equipment \4\ within one year of the enactment of AEMTCA. (42 U.S.C. 
6295(e)(5)(B)) The final rule must replace the energy factor (EF), 
thermal efficiency (TE), and standby loss (SL) metrics with a uniform 
efficiency descriptor. (42 U.S.C. 6295(e)(5)(C)) On July 11, 2014, DOE 
published a final rule that fulfilled these requirements. 79 FR 40542 
(July 2014 final rule). AEMTCA requires that, beginning one year after 
the date of publication of DOE's final rule establishing the uniform 
descriptor (i.e., July 13, 2015), the efficiency standards for the 
consumer water heaters and residential-duty commercial water heaters 
identified in the July 2014 final rule must be denominated according to 
the uniform efficiency descriptor established in that final rule (42 
U.S.C. 6295(e)(5)(D)), and that DOE must develop a mathematical 
conversion for converting the measurement of efficiency from the test 
procedures and metrics in effect at that time to the uniform efficiency 
descriptor. (42 U.S.C. 6295(e)(5)(E)(i)-(ii))
---------------------------------------------------------------------------

    \4\ The uniform efficiency descriptor and accompanying test 
procedure apply to commercial water heating equipment with 
residential applications defined in the test procedure final rule 
published July 11, 2014, as a ``residential-duty commercial water 
heater.'' See 79 FR 40542, 40586.
---------------------------------------------------------------------------

    EPCA provides that any covered water heater (i.e., under DOE's 
rulemaking, all consumer water heaters and residential-duty commercial 
water heaters) manufactured prior to the effective date of the UEF test 
procedure final rule (i.e., July 13, 2015) that complied with the 
efficiency standards and labeling requirements applicable at the time 
of manufacture will be considered to comply with the UEF test procedure 
final rule and with any revised labeling requirements established by 
the Federal Trade Commission (FTC) to carry out the UEF test procedure 
final rule. (42 U.S.C. 6295(e)(5)(K)) DOE's interpretation and 
application of this provision are discussed in detail in Section III.F.
    As noted previously, in the July 2014 final rule, DOE amended its 
test procedure for consumer and certain commercial water heaters. 79 FR 
40542. The July 2014 final rule for consumer and certain commercial 
water heaters satisfied the AEMTCA requirements to develop a uniform 
efficiency descriptor to replace the EF, TE, and SL metrics. The 
amended test procedure includes provisions for determining the uniform 
energy factor (UEF), as well as the annual energy consumption of these 
products. Furthermore, the uniform descriptor test procedure can be 
applied to: (1) Consumer water heaters (including certain consumer 
water heaters that are covered products under EPCA's definition of 
``water heater'' at 42 U.S.C. 6291(27), but that were not addressed by 
the previous test method); and (2) commercial water heaters that have 
residential applications. The major modifications to the EF test 
procedure to establish the uniform descriptor test method included the 
use of multiple draw patterns and different draw patterns, and changes 
to the set-point temperature. In addition, DOE expanded the scope of 
the test method to include all storage volumes, specifically by 
including test procedure provisions that are applicable to water 
heaters with storage volumes between 2 gallons (7.6 L) and 20 gallons 
(76 L), and to clarify applicability to electric instantaneous water 
heaters. DOE also established a new definition for ``residential-duty 
commercial water heater'' and re-categorized certain commercial water 
heaters into this class.
    This rulemaking is intended to satisfy the requirements of AEMTCA 
to develop a mathematical conversion factor for converting the EF, TE, 
and SL metrics to the UEF metric. (42 U.S.C. 6295(e)(5)(E)) As an 
initial step in conducting this rulemaking, DOE published a notice of 
proposed rulemaking on April 14, 2015, which included proposed 
mathematical conversion factors and proposed updates to the energy 
conservation standards. 80 FR 20116.
    The Energy Efficiency Improvement Act of 2015 (EEIA 2015) (Pub. L. 
114-11) was enacted on April 30, 2015. Among other things, EEIA 2015 
added a definition of ``grid-enabled water heater'' to EPCA's energy 
conservation standards for consumer water heaters. (42 U.S.C. 
6295(e)(6)(A)(ii)) These products are intended for use as part of an 
electric thermal storage or demand response program. One of the 
criteria in EPCA that defines a ``grid-enabled water heater'' is the 
requirement that it meet a certain energy factor (specified by a 
formula set forth in the statute), or an equivalent alternative 
standard that DOE may prescribe. Id. On August 11, 2015, DOE published 
a final rule in the Federal Register to implement the changes to EPCA 
by placing the energy conservation standards and related definitions in 
the Code of Federal Regulations (CFR). 80 FR 48004. As the energy 
conservation standard for grid-enabled water heaters is in terms of 
energy factor, DOE is addressing these products in this notice to 
propose a mathematical conversion and updated energy conservation 
standard in terms of UEF.

II. Summary of the Supplemental Notice of Proposed Rulemaking

    In this SNOPR, DOE proposes to establish a mathematical conversion 
factor between the values determined using the EF, TE, and SL test 
procedures (including the first-hour rating or maximum gallons per 
minute (GPM) rating, as applicable), and the values that would be 
determined using the uniform efficiency descriptor test procedure 
established in the July 2014 final rule (i.e., UEF and first-hour 
rating or maximum GPM rating). After further analysis and review of the 
public comments received in response to the April 2015 NOPR, DOE is 
publishing this SNOPR to: (1) Update the proposed mathematical 
conversion factors based on new test data received after the 
publication of the April 2015 NOPR; (2) propose to update the 
approaches considered for developing the conversion factors for 
standard and low NOX non-condensing gas fired storage water 
heaters, condensing storage water heaters, tabletop water heaters, heat 
pump water heaters and residential-duty water heaters; and (3) propose 
a new approach for denominating the existing energy conservation 
standards in terms of the new uniform energy factor metric.
    Other than the specific amendments newly proposed in this SNOPR, 
DOE

[[Page 59740]]

continues to propose the amendments originally included in the April 
2015 NOPR. 80 FR 20116 (April 14, 2015). For the reader's convenience, 
DOE has reproduced in this SNOPR the entire body of latest proposed 
regulatory text from the April 2015 NOPR, amended as appropriate 
according to these proposals. DOE's supporting analysis and discussion 
for the portions of the proposed regulatory text not affected by this 
SNOPR may be found in the April 2015 NOPR.
    The mathematical conversion factor required by AEMTCA is a bridge 
between the values \5\ obtained through testing under the EF, TE, and 
SL test procedures and those obtained under the uniform efficiency 
descriptor test procedure published in the July 2014 final rule. DOE 
conducted a series of tests on the classes of water heaters included 
within the scope of this rulemaking (see section III.B for details on 
the scope) and relied upon that test data and test data submitted by 
interested parties to develop the proposals in this SNOPR. DOE used the 
test data, along with the approaches described in section III.C, to 
calculate the conversion factors proposed in this SNOPR. To develop 
conversion factors for this SNOPR, DOE generally used the same 
methodology as proposed in the April 2015 NOPR (with several exceptions 
discussed in more detail in section III.E.2), and presents in this 
document the updated conversion factors based on the inclusion of 
additional test data. Subsequently, DOE used the conversion factors to 
derive minimum energy conservation standards in terms of UEF, as shown 
in Table II.1 and Table II.2. For this SNOPR, DOE adopted a new 
approach to denominating the energy conservation standards in terms of 
the UEF metric, which is explained in detail in section III.E.3. The 
proposed standards denominated in UEF are neither more nor less 
stringent than the EF-denominated standards for consumer water heaters 
(as amended by the April 2010 final rule) and for commercial water-
heating equipment based on the thermal efficiency and standby loss 
metrics.
---------------------------------------------------------------------------

    \5\ The term ``represented values'' includes all efficiency or 
performance-related information included in product ratings, 
nameplates, public representations (literature, product sheets, 
etc.).

                    Table II.1--Proposed Consumer Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
                                       Rated storage volume and
           Product class                   input rating (if            Draw pattern        Uniform energy factor
                                             applicable)
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage Water Heater.....  <20 gal....................  Very Small............  0.2471-(0.0002 x Vr).
                                                                  Low...................  0.5132-(0.0012 x Vr).
                                                                  Medium................  0.5827-(0.0015 x Vr).
                                                                  High..................  0.6507-(0.0019 x Vr).
                                     >=20 gal and <=55 gal......  Very Small............  0.3456-(0.0020 x Vr).
                                                                  Low...................  0.5982-(0.0019 x Vr).
                                                                  Medium................  0.6483-(0.0017 x Vr).
                                                                  High..................  0.6920-(0.0013 x Vr).
                                     >55 gal and <=100 gal......  Very Small............  0.6470-(0.0006 x Vr).
                                                                  Low...................  0.7689-(0.0005 x Vr).
                                                                  Medium................  0.7897-(0.0004 x Vr).
                                                                  High..................  0.8072-(0.0003 x Vr).
                                     >100 gal...................  Very Small............  0.1755-(0.0006 x Vr).
                                                                  Low...................  0.4671-(0.0015 x Vr).
                                                                  Medium................  0.5719-(0.0018 x Vr).
                                                                  High..................  0.6916-(0.0022 x Vr).
Oil-fired Storage Water Heater.....  <=50 gal...................  Very Small............  0.1822-(-0.0001 x Vr).
                                                                  Low...................  0.5313-(0.0014 x Vr).
                                                                  Medium................  0.6316-(0.0020 x Vr).
                                                                  High..................  0.7334-(0.0028 x Vr).
                                     >50 gal....................  Very Small............  0.1068-(0.0007 x Vr).
                                                                  Low...................  0.4190-(0.0017 x Vr).
                                                                  Medium................  0.5255-(0.0021 x Vr).
                                                                  High..................  0.6438-(0.0025 x Vr).
Electric Storage Water Heaters.....  <20 gal....................  Very Small............  0.7836-(0.0013 x Vr).
                                                                  Low...................  0.8939-(0.0008 x Vr).
                                                                  Medium................  0.9112-(0.0007 x Vr).
                                                                  High..................  0.9255-(0.0006 x Vr).
                                     >=20 gal and <=55 gal......  Very Small............  0.8808-(0.0008 x Vr).
                                                                  Low...................  0.9254-(0.0003 x Vr).
                                                                  Medium................  0.9307-(0.0002 x Vr).
                                                                  High..................  0.9349-(0.0001 x Vr).
                                     >55 gal and <=120 gal......  Very Small............  1.9236-(0.0011 x Vr).
                                                                  Low...................  2.0440-(0.0011 x Vr).
                                                                  Medium................  2.1171-(0.0011 x Vr).
                                                                  High..................  2.2418-(0.0011 x Vr).
                                     >120 gal...................  Very Small............  0.6802-(0.0003 x Vr).
                                                                  Low...................  0.8620-(0.0006 x Vr).
                                                                  Medium................  0.9042-(0.0007 x Vr).
                                                                  High..................  0.9437-(0.0007 x Vr).
Tabletop Water Heater..............  All........................  Very Small............  0.6323-(0.0058 x Vr).
                                                                  Low...................  0.9188-(0.0031 x Vr).
                                                                  Medium................  0.9577-(0.0023 x Vr).
                                                                  High..................  0.9884-(0.0016 x Vr).

[[Page 59741]]

 
Instantaneous Gas-fired Water        <2 gal and >50,000 Btu/h...  Very Small............  0.7964-(0.0000 x Vr).
 Heater.                                                          Low...................  0.8055-(0.0000 x Vr).
                                                                  Medium................  0.8070-(0.0000 x Vr).
                                                                  High..................  0.8086-(0.0000 x Vr).
                                     >=2 gal or <=50,000 Btu/h..  Very Small............  0.3013-(0.0023 x Vr).
                                                                  Low...................  0.5421-(0.0024 x Vr).
                                                                  Medium................  0.5942-(0.0021 x Vr).
                                                                  High..................  0.6415-(0.0017 x Vr).
Instantaneous Oil-fired Water        All........................  Very Small............  0.1430-(0.0015 x Vr).
 Heater.                                                          Low...................  0.4455-(0.0023 x Vr).
                                                                  Medium................  0.5339-(0.0023 x Vr).
                                                                  High..................  0.6245-(0.0021 x Vr).
Instantaneous Electric Water Heater  All........................  Very Small............  0.9161-(0.0039 x Vr).
                                                                  Low...................  0.9159-(0.0009 x Vr).
                                                                  Medium................  0.9160-(0.0005 x Vr).
                                                                  High..................  0.9161-(0.0003 x Vr).
Grid-Enabled Water Heater..........  >75 gal....................  Very Small............  1.0136-(0.0028 x Vr).
                                                                  Low...................  0.9984-(0.0014 x Vr).
                                                                  Medium................  0.9853-(0.0010 x Vr).
                                                                  High..................  0.9720-(0.0007 x Vr).
----------------------------------------------------------------------------------------------------------------
*Vr is the rated storage volume which is the water storage capacity of a water heater (in gallons), as specified
  by the manufacturer.


           Table II.2--Proposed Residential-Duty Commercial Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
                    Product class                              Draw pattern             Uniform energy factor
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage....................................  Very Small..................  0.2670--(0.0009 x Vr).
                                                       Low.........................  0.5356--(0.0012 x Vr).
                                                       Medium......................  0.5996--(0.0011 x Vr).
                                                       High........................  0.6592--(0.0009 x Vr).
Oil-fired Storage....................................  Very Small..................  0.2932--(0.0015 x Vr).
                                                       Low.........................  0.5596--(0.0018 x Vr).
                                                       Medium......................  0.6194--(0.0016 x Vr).
                                                       High........................  0.6740--(0.0013 x Vr).
Electric Instantaneous...............................  Very Small..................  0.80.
                                                       Low.........................  0.80.
                                                       Medium......................  0.80.
                                                       High........................  0.80.
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume, which is the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.

    The conversion factor formulas may be used for one year beginning 
on the date of publication of the conversion factor final rule in the 
Federal Register. After that time, all representations regarding energy 
efficiency or energy use must be based on testing (either directly or 
through the application of an AEDM, where permitted). In addition, EPCA 
requires that a water heater be considered to comply with the July 2014 
final rule on and after July 13, 2015 (the effective date of the July 
2014 final rule) and with any revised labeling requirements established 
by the FTC to carry out the July 2014 final rule if that water heater 
basic model was manufactured prior to July 13, 2015, and complied with 
the applicable efficiency standards and labeling requirements in effect 
prior to July 13, 2015. (See 42 U.S.C. 6295(e)(5)(K)) Sections III.F 
and III.G explain that DOE intends to address various issues related to 
the transition from the metrics in effect prior to July 13, 2015, 
through the use of enforcement policies.

III. Discussion

A. Purpose

    As discussed in section I, DOE has undertaken this rulemaking to 
establish a mathematical conversion factor as a result of requirements 
added to EPCA by AEMTCA. (42 U.S.C. 6295(e)(5)) EPCA requires DOE to 
establish a uniform efficiency descriptor for consumer water heaters 
and commercial water heaters, and to establish a mathematical 
conversion factor to translate from the EF, TE, and SL descriptors to 
the uniform efficiency descriptor established by DOE. Id. In the July 
2014 test procedure final rule, DOE established UEF as the uniform 
efficiency descriptor, and adopted a test method for measuring UEF for 
consumer and certain commercial water heaters. 79 FR 40542 (July 11, 
2014). The current rulemaking addresses the mathematical conversion 
factor required by EPCA (see 42 U.S.C. 6295(e)(5)(E)) and the 
requirement that the efficiency standard be denominated according to 
the uniform efficiency descriptor (i.e., UEF) (see 42 U.S.C. 
6295(e)(5)(D)(i)).
    Based on review of the test results used to develop the 
mathematical conversion factors, DOE has found that different water 
heaters are impacted in different ways by the new test method and 
metric, depending on the specific design and characteristics of the 
water heater. Water heaters have numerous attributes that impact energy 
efficiency and performance, and the changes to the test method and 
metrics impact each water heater model differently, often in ways that 
are difficult to predict. For example, two electric water heaters with 
the same rated storage volume, input rating, first-hour rating, and 
energy factor rating (all represented values published under the EF 
test method as indicators of water heater performance)

[[Page 59742]]

have been shown by testing to have different measured first-hour 
ratings and uniform energy factors when tested under the new test 
procedure.
    Given the number of models currently available in the market (756 
unique basic models as of September 2015), it would not be practical to 
analyze each model individually to determine the change in represented 
values under the new test procedure. Rather, DOE has analyzed a subset 
of models that are representative of the market as a whole (see section 
III.D for further discussion of the models tested for this rule). This 
approach is consistent with the statutory mandate, which instructs DOE 
to develop ``a mathematical conversion factor.'' (42 U.S.C. 
6295(e)(5)(E)) DOE recognizes that the phrase ``mathematical conversion 
factor'' does not require DOE to generate a single number applicable to 
all water heaters. For one thing, DOE believes that, despite the use of 
the word ``factor,'' in the singular, the statute permits the use of a 
conversion equation involving several numbers and mathematical 
operations besides multiplication. Still, the phrasing suggests that 
DOE should develop a formula that is broadly applicable, rather than 
generate a table of equivalencies stating the exact UEF equivalent for 
every individual product on the market.
    Because each water heater is impacted differently, it would be 
impossible to develop a single equation, or reasonable set of 
equations, that could be used to model the energy performance of every 
water heater exactly under the new test method. Therefore, the purpose 
of this mathematical conversion factor is to develop an equation that 
will be able to reasonably predict a water heater's energy efficiency 
under the UEF test method based on values measured under the EF, TE, or 
SL test methods for that model.
    Any mathematical conversion will have some amount of residual 
difference between predicted and measured values that is inherent when 
applying a mathematical equation (or multiple equations for different 
types of water heaters) to predict the energy efficiency performance or 
delivery capacity of a large set of models. In this rule, DOE has 
sought to minimize the amount of difference between predicted and 
actual performance in several ways. DOE incorporated as much test data 
as was practical and available, and which represented models currently 
on the market (see section III.D). DOE considered several attributes 
that could have a large impact on the test results under both the new 
and old metrics, and included those as appropriate when developing the 
mathematical conversion, which led to a set of equations for water 
heaters with certain different characteristics (e.g., different fuel 
types, different nitrogen oxide (NOX) emissions levels). DOE 
also explored several options for identifying the most accurate 
methodologies for developing the mathematical conversion equations (see 
section III.C). In addition, DOE sought feedback from interested 
parties and incorporated suggestions for improving the mathematical 
conversions when the suggested changes in approach resulted in 
conversion equations that were better predictors of actual measured 
performance.
    As noted previously, this rulemaking also addresses the requirement 
that the efficiency standard be denominated in terms of UEF, and in 
this notice DOE proposes energy conservation standard levels using the 
UEF metric. (42 U.S.C. 6295(e)(5)(D)(i)) As discussed in section I, DOE 
may not adopt a standard that reduces the stringency of the existing 
standards, due to the ``anti-backsliding'' clause. (42 U.S.C. 
6295(o)(1); 6313(a)(6)(B)(iii)(I)) Further, EPCA requires that the 
mathematical conversion factor not affect the minimum efficiency 
requirements. (42 U.S.C 6295(e)(5)(E)(iii)).
    The methodology proposed in section III.E.3 for translating the 
standards is intended to ensure equivalent stringency between the 
existing standards (using EF, TE, and SL metrics) and the proposed 
updated standards (using UEF). Due to differences in water heater 
performance under the different test methods discussed in the preceding 
paragraphs, some models will perform better, and others worse, under 
the new test method than they did under the previous test method. Even 
though the stringency with respect to a specific model may vary based 
on the characteristics and performance of that model, the proposed 
approach for translating the standard is designed to maintain the same 
stringency for each product class as a whole. Because DOE's goal is to 
maintain the same stringency of the standards under the EF, TE, and SL 
metrics (i.e., the standards in terms of the new UEF metric are neither 
more nor less stringent), and because individual models are impacted 
differentially by the change in test method and metric, some models 
that were previously minimally compliant will perform better than the 
translated UEF minimum, and others will perform worse. The possibility 
of such outcomes would not, by itself, mean that the conversion 
methodology was improper. As noted above, the possibility of some 
deviation for individual products is inherent in the use of a broad-
based conversion equation. However, because the statute nonetheless 
mandates that the Department develop a ``mathematical conversion 
factor,'' DOE understands the statute to permit the consequences that 
naturally follow from that approach.

B. Scope

    The purpose of this section is to describe DOE's process for 
categorizing water heaters and establishing the range of units to be 
considered in this mathematical conversion factor rulemaking. DOE 
initially outlined the scope of this rulemaking in the April 2015 NOPR. 
80 FR 20116, 20122-24 (April 14, 2015). In summary, this rulemaking 
includes all covered consumer water heaters, as well as commercial 
water heaters meeting the definition of ``residential-duty commercial 
water heater.'' In the NOPR, DOE stated that it was not including water 
heaters that were not previously subject to the test procedures or 
standards for energy factor established in the Code of Federal 
Regulations in the scope of the conversion factor, as they are not 
required to be tested and rated for efficiency under the DOE test 
method. Id. Table III.1 lists the consumer water heaters that, for this 
reason, DOE did not propose a mathematical conversion factor in the 
NOPR.

   Table III.1--Consumer Water Heaters Not Covered in the NOPR by the
                     Mathematical Conversion Factor
------------------------------------------------------------------------
                                           Description of criteria for
             Product class                  exclusion from conversion
                                                    rulemaking
------------------------------------------------------------------------
Gas-fired Storage......................  Rated Storage Volume >=2 gal
                                          and <20 gal or >100 gal.
Oil-fired Storage......................  Rated Storage Volume >50 gal.
Electric Storage.......................  Rated Storage Volume >=2 gal
                                          and <20 gal or >120 gallons.
Tabletop...............................  Rated Storage Volume >=2 gal
                                          and <20 gal or >120 gallons.
Gas-fired Instantaneous................  Rated Input <=50,000 Btu/h;
                                          Rated Storage Volume >=2 gal.

[[Page 59743]]

 
Electric Instantaneous.................  Rated Storage Volume >=2 gal.
Oil-fired Instantaneous................  All.
------------------------------------------------------------------------

    DOE has further considered the applicability of standards to the 
products listed in Table III.1 and proposes to clarify that the initial 
energy conservation standards in EPCA, as listed in Table I.1, are 
applicable to gas-fired, electric, and tabletop water heaters below 20 
gallons storage volume; gas-fired water heaters above 100 gallons 
storage volume; oil-fired water heaters above 50 gallons storage 
volume; electric and tabletop water heaters above 120 gallons storage 
volume; gas-fired instantaneous water heaters with an input at or below 
50,000 Btu/h or at or above 2 gallons storage volume; electric 
instantaneous water heaters at or above 2 gallons; and oil-fired 
instantaneous water heaters. These products were not considered in 
DOE's rulemakings that culminated in the April 16, 2010 and January 17, 
2001 final rules (75 FR 20112 and 66 FR 4474, respectively), and 
accordingly, the standards adopted in those final rules are not 
applicable to these products.
    DOE notes that EPCA's definitions for consumer water heaters do not 
place any limitation on the storage volume or specify a minimum fuel 
input rate for gas-fired instantaneous water heaters. Thus, DOE has 
tentatively concluded that the initial standards for water heaters 
included in EPCA were intended to cover all water heaters meeting the 
definition of a ``water heater'' at 42 U.S.C. 6291(27) and would apply 
regardless of the storage volume, and without a lower limit on the fuel 
input rating for gas-fired instantaneous water heaters.
    In this SNOPR, DOE used the applicable conversion equations to 
convert the EPCA-established standards applicable to the products in 
Table III.1 from EF to UEF. For electric water heaters, as discussed in 
section I, in the October 17, 1990 test procedure final rule, DOE 
determined that the standard set by EPCA required adjustment under 42 
U.S.C. 6293(e) due to the effect of the change in test procedure. 55 FR 
42162, 42164. DOE believes the impact on measured energy characterized 
in the October 1990 test procedure final rule resulting from the change 
in the test procedure is valid for all consumer electric water heaters 
and not just those limited to the gallon sizes specified in the October 
1990 test procedure final rule. Accordingly, DOE has used the standard 
level adopted in the 1990 test procedure final rule for establishing 
converted UEF standards for electric water heaters with storage volumes 
below 20 gallons and above 120 gallons.
    DOE has found that oil-fired instantaneous water heaters exist on 
the market and are available for sale within the United States. Oil-
fired instantaneous water heaters were not defined under the EF test 
procedure, nor were these products defined by DOE at 10 CFR 430.2 prior 
to the effective date of the July 2014 test procedure final rule that 
established the UEF metric. However, oil-fired instantaneous water 
heaters are defined by EPCA at 42 U.S.C. 6291(27)(B), were added to the 
definitions at 10 CFR 430.2 in the July 2014 test procedure final rule, 
and are covered by the UEF test procedure. Because oil-fired 
instantaneous water heaters were not previously tested to the EF test 
procedure, a conversion factor is not necessary (as manufacturers would 
not have EF ratings to convert). Rather, manufacturers of oil-fired 
instantaneous water heaters who wish to make representations of 
efficiency should test to the UEF metric. However, DOE must still 
convert the energy conservation standard established by EPCA from EF to 
UEF. The steps taken for this conversion are explained in section 
III.E.3.
    As noted in section I, EPCA was recently amended to define and set 
efficiency requirements for grid-enabled water heaters in terms of EF, 
so DOE has included the development of a conversion factor and updated 
standard for these products in this SNOPR. DOE has tentatively 
determined that these products do not meet the criteria for exclusion 
from the UEF metric.
    Only commercial water heaters meeting the definition of 
``residential-duty commercial water heater'' are subject to the uniform 
efficiency descriptor test method, while all other commercial water 
heaters are not. As a result, this conversion only addresses commercial 
water heaters that meet the definition of ``residential-duty commercial 
water heater,'' which includes commercial water heaters that:
    (1) For models requiring electricity, uses single-phase power;
    (2) Are not designed to provide outlet hot water at temperatures 
greater than 180 [deg]F; and
    (3) Are not excluded by the limitations regarding rated input and 
storage volume presented in Table III.2.

 Table III.2--Capacity Limitations for Defining Commercial Water Heaters
       Without Consumer Applications (i.e., Non-Residential-Duty)
------------------------------------------------------------------------
                                            Indicator of non-consumer
           Water heater type                       application
------------------------------------------------------------------------
Gas-fired Storage......................  Rated input >105 kBtu/h; Rated
                                          storage volume >120 gal.
Oil-fired Storage......................  Rated input >140 kBtu/h; Rated
                                          storage volume >120 gal.
Electric Storage.......................  Rated input >12 kW; Rated
                                          storage volume >120 gal.
Gas-fired Instantaneous................  Rated input >200 kBtu/h; Rated
                                          storage volume >2 gal.
Electric Instantaneous.................  Rated input >58.6 kW; Rated
                                          storage volume >2 gal.
Oil-fired Instantaneous................  Rated input >210 kBtu/h; Rated
                                          storage volume >2 gal.
------------------------------------------------------------------------

    Additionally, DOE notes that for several types of water heaters, 
definitional criteria preclude their classification as residential-duty 
commercial water heaters. For example, an electric storage water heater 
with a rated input of greater than 12 kW would not be a residential-
duty commercial water heater, as it is excluded under the

[[Page 59744]]

definition of ``residential-duty commercial water heater'' based on its 
rated input; conversely, an input rating at or below 12 kW would place 
an electric storage water heater in the consumer water heater category 
under EPCA. (See 42 U.S.C. 6291(27)(A)). Therefore, there is no input 
rating at which an electric storage water heater would be classified as 
a residential-duty commercial water heater. Similarly, EPCA defines 
gas-fired instantaneous water heaters with an input of 200,000 Btu per 
hour or less, oil-fired instantaneous water heaters with an input of 
210,000 Btu per hour or less, and heat pump type water heaters with a 
rated input of 12 kW or less, or a rated current of 24 amps or less at 
a rated voltage of not greater than 250 volts, as consumer water 
heaters. (42 U.S.C. 6291(27)(B)). The residential-duty commercial water 
heater criteria in Table III.2 exclude models with input rates above 
the input limits from being residential-duty commercial water heaters. 
Any water heaters above the applicable limits would be considered non-
residential-duty commercial water heaters, and any water heaters at or 
below the applicable limits would be consumer water heaters. Therefore, 
in a NOPR for test procedures for certain commercial water heating 
equipment published on May 9, 2016 (``May 2016 CWH TP NOPR''), DOE is 
proposing to expressly exclude these four classes--electric storage 
water heaters, heat pump water heaters, gas-fired instantaneous water 
heaters, and oil-fired instantaneous water heaters--from the definition 
for ``residential-duty commercial water heater'' codified at 10 CFR 
431.102. 81 FR 28588, 28607, 28637. Consequently, a mathematical 
conversion and a standard in terms of UEF are only necessary for the 
types of water heaters that can be defined as residential-duty 
commercial water heaters: gas-fired storage water heaters, oil-fired 
storage water heaters, and electric instantaneous water heaters.
    In response to the April 2015 NOPR proposals, Air-Conditioning, 
Heating, and Refrigeration Institute (AHRI) commented that residential-
duty commercial electric storage water heaters should have a conversion 
because electric water heaters that were designed with input rates less 
than or equal to 12 kW and deliver water at temperatures of 180 [deg]F 
were previously (i.e., before changes to the DOE definition for 
``electric storage water heater'' were adopted in the July 2014 test 
procedure final rule) not considered to be consumer products. (AHRI, 
No. 13 at p. 6) As discussed in the preceding paragraph, there are no 
electric storage water heaters that would be classified as residential-
duty commercial water heaters. EPCA includes as consumer electric 
storage water heaters those having an input rating less than or equal 
to 12 kW and does not distinguish between the consumer and commercial 
classifications by delivery temperature. (42 U.S.C. 6291(27)(A)) 
Therefore, electric storage water heaters with input rates at or below 
12 kW are covered consumer products (rather than commercial equipment) 
regardless of the delivered water temperature. Thus, the product that 
AHRI discusses--electric storage water heaters rated at or below 12 kW 
but designed to deliver water at temperatures above 180 [deg]F--would 
be classified as a consumer product under EPCA and would not be 
eligible for classification as a residential-duty commercial water 
heater under DOE's definitions at 10 CFR 431.102. DOE is, therefore, 
not proposing a conversion factor for residential-duty commercial 
electric storage water heaters, as there can be no such equipment. As 
proposed in this SNOPR, a product such as that described by AHRI would 
rely on the conversion that has been proposed for electric storage 
water heaters generally. Further, although electric storage water 
heaters that are designed with input ratings less than or equal to 12 
kW and to deliver water at temperatures of 180 [deg]F were not included 
in the consumer water heater energy factor test procedure,\6\ they are 
consumer products. As consumer products, such water heaters are not 
required to be tested under the metric for commercial electric storage 
water heaters (i.e., standby loss). Rather, since such products are 
classified as consumer products under the statute, DOE proposes to 
clarify that they should be tested and rated under the UEF test method. 
In the event that the UEF test method does not apply, manufacturers 
should submit a petition for waiver DOE (see 10 CFR 430.27) that would 
allow them to test and rate their products to the appropriate consumer 
water heater efficiency metrics. DOE is proposing in a separate 
rulemaking to clarify the definitions for specific kinds of consumer 
water heaters by removing the specifications related to the water 
delivery temperature. 81 FR 28636. Finally, DOE notes that a water 
heater that meets the definition of a consumer electric storage water 
heater must be tested and rated as a consumer electric storage water 
heater, even if it is marketed as part of a commercial product line.
---------------------------------------------------------------------------

    \6\ Prior to being updated by the July 11, 2014 final rule (79 
FR 40542, 40567), the Uniform Test Method for Measuring the Energy 
Consumption of Water Heaters at appendix E to subpart B of 10 CFR 
430 included a definition for ``Electric Storage-type Water Heater'' 
that included only, in relevant part, models designed to heat and 
store water at a thermostatically-controlled temperature of less 
than 180 [deg]F.
---------------------------------------------------------------------------

    AHRI also commented that residential-duty electric instantaneous 
water heaters exist as defined in the UEF test procedure and, 
therefore, need a conversion. (AHRI, No. 13 at p. 6) DOE agrees that 
residential-duty commercial electric instantaneous water heaters exist 
on the market and that they are currently subject to the commercial 
water heating equipment test procedures. 10 CFR 431.106. Commercial 
electric instantaneous water heaters are also subject to the energy 
conservation standards for commercial instantaneous water heaters 
established in EPCA. (42 U.S.C. 6313(a)(5)(D)-(E)).\7\ Specifically, 
for commercial instantaneous water heaters with a storage volume of 
less than 10 gallons, the minimum thermal efficiency is 80 percent. For 
commercial instantaneous water heaters with a storage volume of 10 
gallons or greater, the minimum thermal efficiency is 77 percent, and 
the maximum standby loss is 2.30 + (67/Measured Storage Volume [in 
gallons]) percent per hour. Because residential-duty electric 
instantaneous commercial water heaters are required to have a storage 
volume of 2 gallons or less, the former standard level would apply to 
this equipment. 10 CFR 431.102. Therefore, DOE has tentatively decided 
to provide a mathematical conversion factor for residential-duty 
commercial electric instantaneous water heaters. DOE also proposes 
energy conservation standards for residential-duty commercial electric 
instantaneous water heaters denominated in the UEF metric. See section 
III.E.2.d for further discussion of the mathematical conversion for 
this equipment.
---------------------------------------------------------------------------

    \7\ In a NOPR for energy conservation standards for commercial 
water heating equipment published on May 31, 2016, DOE proposed to 
codify the energy conservation standards in EPCA for commercial 
electric instantaneous water heaters at 10 CFR 431.110. 81 FR 34440, 
34535-36.
---------------------------------------------------------------------------

C. Approaches for Developing Conversions

    This section provides the approaches that DOE is considering in 
developing equations to convert from prior metrics to the new metrics, 
including the benefits and drawbacks of each approach and details on 
how the equations were derived.
    To develop the conversions between the prior metrics (first-hour 
rating,

[[Page 59745]]

maximum GPM, energy factor, thermal efficiency, standby loss) and the 
new metrics (first-hour rating, maximum GPM, uniform energy factor), 
DOE has broadly considered two different approaches. The first, termed 
``analytical methods,'' uses equations based on the fundamental physics 
of water heater operation to predict how changes in test parameters 
lead to changes in the performance metrics. The second approach, termed 
``empirical regression,'' is a purely data-driven approach that uses 
experimental data and regressions to develop equations that relate the 
prior metrics to the new ones. In addition, DOE is also considering a 
hybrid approach that uses both techniques.
1. Overview of Analytical Methods Approach
    The analytical methods approach relies on basic equations of heat 
transfer and thermodynamics, as well as established understanding of 
the behavior of water heaters, to estimate the metric based on a set of 
known parameters for the water heater, environment, and test pattern. 
Such an approach typically yields an equation or set of equations that 
can be solved to ultimately yield the metric of interest, either an 
efficiency or delivery capacity. An attempt is then made to manipulate 
the equations for the metrics to yield an equation that expresses the 
new metrics in terms of the old metrics and other known quantities. 
Analytical methods have the advantage of capturing known effects on 
performance without conducting a series of experiments. Additionally, a 
properly formulated relationship would be expected to be applicable to 
all water heaters on the market. Analytical approaches do have some 
drawbacks, however. Most notably, these methods only account for 
factors that are known to impact performance and which can be readily 
estimated. There may be other phenomena that affect performance that 
may not be included in the known models. Second, application of these 
models often require assumptions about conditions. For example, one may 
need to assume a particular temperature of the water in the water 
heater despite the fact that it is known that there is variation in 
that temperature. Lastly, while an analytical model reduces the amount 
of tests needed to generate a conversion equation, a thorough set of 
experiments is still necessary to validate the model. Because it is 
based on fundamental physics, though, an analytical model can typically 
be extended with more confidence to a water heater that has not been 
tested than would a model based purely on experimental data.
    Section III.C.4 discusses approaches that DOE has considered for 
developing analytical models to convert from prior metrics to new 
metrics for both delivery capacity and energy efficiency of water 
heaters under the uniform energy factor rating method.
2. Overview of Empirical Regression Approach
    The second category of conversion factors considered by DOE is 
empirical regression. In this approach, a collection of water heaters 
is tested according to both the former test procedure and the new test 
procedure. The resultant performance metrics, as well as other data on 
the units (e.g., storage volume, input rate), are compiled, and 
statistical techniques are used to create correlations that relate the 
new performance metrics to the prior metrics and characteristics. No 
consideration of the underlying physics is used in this approach. 
Rather, it is purely a data-driven method. The advantage of this 
approach is that the results are not biased by existing assumptions on 
how a water heater should behave under given conditions, with the 
results representing exactly what is observed in actual comparison 
testing. This approach should capture all factors that affect the 
energy efficiency and delivery capacity, even though those factors may 
not be known a priori.
    Empirical regression also has some drawbacks. One drawback is that 
the resulting equations are most confidently applied to water heaters 
with attributes similar to those that were tested. Consequently, to 
minimize uncertainties, a large sample for testing is often appropriate 
to capture more fully many of the nuances in water heater design. If 
extended to units not sufficiently similar to those that were tested, 
the equations may produce unacceptably large differences between 
predicted and measured values if a feature on the untested model has an 
effect that is not captured in the experimental data. Another major 
drawback is that empirical regression is susceptible to experimental 
uncertainties. While uncertainties can be reduced through careful 
quality checks of experimental data, uncertainty is present in any 
test. The empirical regressions, being based on many samples across 
multiple different units, will further reduce the uncertainty, but some 
amount of uncertainty in the regression may be unavoidable.
    Section III.C.5 presents the details of the empirical regression 
approaches explored by DOE.
3. Overview of Hybrid Approach
    DOE has also considered a combination of the analytical methods 
approach and empirical regression approach, termed a hybrid approach. 
In this approach, a broad range of water heaters are tested, as would 
be done in using empirical regression. An additional factor is added to 
the list of attributes that is examined in the regression; this factor 
uses the analytical methods to first estimate the converted value. This 
estimate of the revised performance metric (maximum GPM, first-hour 
rating, or UEF) for each water heater tested is then used as an 
independent variable in a regression to determine the measured UEF. DOE 
believes that this approach takes advantage of the ability of the 
analytical methods approach to capture the major known factors that 
affect the efficiency, yet adds the additional step of regression to 
account for any influences that are not well described by the 
analytical methods.
4. Analytical Methods Approach
a. Maximum GPM
    For flow-activated water heaters, the delivery capacity under the 
EF and UEF test procedures is determined by the 10-minute maximum GPM 
rating test. During this test, the water heater runs at maximum firing 
rate to raise the temperature from a starting value of 58[emsp14][deg]F 
 2[emsp14][deg]F to the prescribed delivery temperature. 
This flow rate is determined by the following equation:
[GRAPHIC] [TIFF OMITTED] TP30AU16.022

where V is the volumetric flow rate of water, Q is the firing rate, 
[eta]r is the recovery efficiency, [rho] is the density of 
the delivered water, cp is the specific heat of the 
delivered water, Tdel is the delivered water temperature, 
and Tin is the inlet water temperature.
    In the April 14, 2015 NOPR, DOE proposed to convert prior maximum 
GPM represented values to those represented values under the amended 
test procedure by accounting only for the change in Tdel 
from 135[emsp14][deg]F to 125[emsp14][deg]F and for the change in the 
density and specific heat of water at the new delivery temperature. 80 
FR 20116, 20125. The equation above can be evaluated for both delivery 
temperatures, and an expression for the maximum GPM under the uniform 
efficiency descriptor (VUED) as a function of the prior maximum GPM 
rating (Vex) was proposed as:

VUED = 1.147Vec


[[Page 59746]]


    Northwest Energy Efficiency Alliance (NEEA) commented that the 
relatively simple physics associated with water flow rate and 
temperature rise made this conversion relatively robust, but that some 
anomalies were present in comparing measured and analytical ratings. 
(NEEA, No. 15 at p. 6) As noted in the data presented in the NOPR, DOE 
found this conversion equation to match well with measured data and is 
proposing it in a slightly modified version as the method to convert 
from the prior maximum GPM rating to the maximum GPM rating under the 
uniform energy descriptor. In the NOPR, the specific heat values were 
calculated using the delivery temperatures of 125[emsp14][deg]F and 
135[emsp14][deg]F for the EF and UEF test procedures, respectively. In 
this SNOPR, the specific heat values are calculated using the average 
of the delivery temperature (i.e., 125[emsp14][deg]F and 
135[emsp14][deg]F for the EF and UEF test procedures, respectively) and 
the inlet temperature (i.e., 58[emsp14][deg]F for both test 
procedures). Further, the multiplier is shown to the fourth decimal 
place to be more consistent with the other equations presented in this 
SNOPR. Upon recalculation using appropriate values of density and 
specific heat, the proposed conversion equation is:

VUED = 1.1461Vec
b. First-Hour Rating
    In the April 14, 2015 NOPR, DOE indicated that it was not aware of 
any analytical models that would mathematically represent the 
conversion of first-hour ratings from the prior test method to the 
amended test method. 80 FR 20116, 20125. NEEA questioned why DOE would 
make a statement in this regard, but then go on to propose a 
mathematical construct for doing so. (NEEA, No. 15 at p. 5) DOE notes 
that the mathematical construct proposed to convert first-hour ratings 
is based purely on regression analysis to measured data and that DOE 
used the terminology ``analytical model'' to represent physics-based 
equations that relate the two quantities. No comments were received 
that proposed an analytical model for converting first-hour ratings, so 
DOE continues to propose to use data-driven regression analysis to 
convert prior first-hour ratings to amended first-hour ratings, as 
discussed in section III.E.2.
c. Uniform Energy Factor
    A number of changes to the 24-hour simulated-use test will alter 
the represented values of water heater energy efficiency under the 
prior water heater test procedures as compared to the represented 
values obtained under the uniform efficiency descriptor test method. 
Among the key changes that are expected to alter the efficiency metric 
for consumer water heaters are: (1) A different volume of water 
withdrawn per test; (2) a change in the draw pattern (i.e., number of 
draws, flow rates during draws, timing of draws) applied during the 
test; (3) reduction of the test temperature from an average stored 
temperature of 135[emsp14][deg]F to a delivered water temperature of 
125[emsp14][deg]F; and (4) removal of the stipulation to normalize the 
energy consumption to maintain a prescribed average water temperature 
within the storage tank. Residential-duty commercial water heaters will 
see a change from the thermal efficiency and standby loss metrics to 
the UEF, which consists of an entirely new approach for rating 
efficiency.
i. Consumer Storage Water Heaters
    In the April 14, 2015 NOPR, DOE proposed to use the Water Heater 
Analysis Model (WHAM) as a basis for conversion. 80 FR 20116, 20126-27. 
This model first determines the amount of energy input (Q) over a 24-
hour period using the following equation:
[GRAPHIC] [TIFF OMITTED] TP30AU16.023

where [rho] is the density of water, cp is the specific heat 
of water, [eta]r is the recovery efficiency, V is the volume 
of water delivered per day, Tdel is the delivered water 
temperature, Tin is the inlet water temperature, UA is the 
heat loss factor, Ttank is the average temperature of the 
water stored within the tank of a storage water heater, P is the input 
power to the water heater in Btu/h, Tamb is the average 
ambient temperature during the test, and 24 is the number of hours in 
the test. This equation considers the energy required to heat the water 
that is delivered by the water heater from the inlet water temperature 
up to the delivery temperature and the energy required to make up the 
heat lost from the water heater to the surrounding environment. The 
time over which this standby energy loss is determined is corrected by 
the term with the power in the denominator to account for the fact that 
[eta]r, as calculated in the test, accounts for standby 
energy loss during periods when heat input to the water is activated.
    This calculated energy can then be used to estimate the daily 
efficiency, Eff, under a given daily water demand (e.g., that required 
during the EF test or that required during the UEF test):
[GRAPHIC] [TIFF OMITTED] TP30AU16.024

    Since the EF testing entails a prescribed Tdel 
(135[emsp14][deg]F), Tin (58[emsp14][deg]F), 
Ttank (135[emsp14][deg]F), Tamb 
(67.5[emsp14][deg]F), and V (64.3 gallons), the two equations can be 
solved for the two remaining unknowns, Q and UA. After the equations 
are solved to determine UA, if one assumes that the UA and 
[eta]r do not change under the new test approach, then the 
two equations can be solved again (this time inserting the UA value 
obtained from solving the previous set of equations) to determine the 
values for Q and Eff (i.e., UEF) under the uniform efficiency 
descriptor test method using the prescribed values for the uniform 
efficiency descriptor test procedure of Tdel 
(125[emsp14][deg]F), Tin (58[emsp14][deg]F), 
Ttank (125[emsp14][deg]F), Tamb 
(67.5[emsp14][deg]F), and V (varies depending upon draw pattern).
    DOE received a number of comments with suggested improvements to 
the WHAM model. Several commenters addressed the assumption that the 
average tank temperature, Ttank, is equal to the average 
delivered water temperature, Tdel. Rheem indicated that the 
delivered hot water temperature is greater than the average water 
temperature in the tank due to stratification and that the temperature 
difference needs to be accounted for more accurately in the analytical 
equations. (Rheem, No. 11 at p. 6) AHRI asked DOE to reconsider the 
assumption that the delivered water temperature is the same as the 
stored water temperature. (AHRI, No. 13 at p. 7) Bradford White added 
that the delivered temperature is typically close to the average tank 
temperature for electric water heaters, but this assumption is often 
not correct on gas-fired water heaters that can have a stratified tank 
with an average tank temperature that is much lower than the delivered

[[Page 59747]]

temperature. (Bradford White, No. 14 at p. 2) NEEA commented that DOE 
has incorporated indefensible tank temperature assumptions that are far 
enough off to make the conversion factors significantly inaccurate, and 
that temperature differences between the top and bottom of tall tanks 
can be up to 10[emsp14][deg]F, leading to differences between 
Tdel and Ttank of 5[emsp14][deg]F. (NEEA, No. 15 
at p. 2)
    To address these concerns, DOE examined test data and assessed the 
effect of changes in Ttank on the predictions of the WHAM 
analytical model. The average delivered water temperature during draws 
was compared to the average tank temperature during standby periods for 
a subset of the gas-fired and electric storage water heaters tested. 
For consumer electric storage water heaters, the average delivered 
water temperature was 6.8[emsp14][deg]F higher than the mean tank 
temperature, with a standard deviation of 4.4[emsp14][deg]F. For 
consumer gas-fired water heaters, the delivered water temperature was 
found to be only 1.5[emsp14][deg]F greater than the average tank 
temperature, with a standard deviation of 4[emsp14][deg]F. These 
results raise questions about the statements by commenters that the 
delivered water temperature is always much greater than the average 
tank temperature. DOE's observation in these tests is that on occasion, 
the delivered temperature is less than the average tank temperature 
that was recorded during the standby portion of the test. That 
observation is inconsistent with the commenters' suggestion, and DOE 
has identified several potential reasonable explanations for the 
observations. From examination of test data, it appears that there are 
several periods during the test when a recovery occurs such that there 
is an extended time following the recovery before the start of the next 
draw, meaning that the temperature of the water in the tank has cooled 
from the level it attains after a recovery. Additionally, standby 
periods often occur shortly after a tank recovery, meaning that the 
average tank temperature is relatively high during those periods. These 
two characteristics of the tests could certainly lead to situations 
where the average delivered water temperature is not always 
significantly greater than the average tank temperature during standby.
    Next, DOE compared measured UEF values to the predictions of the 
WHAM model with different settings for Ttank. As discussed 
further later in this section, these WHAM predictions were also 
computed with different assumptions on the changes in recovery 
efficiency and the UA values from the EF test to the UEF test. In all 
cases, an assumption of Ttank = 125[emsp14][deg]F resulted 
in lower root-mean-square deviations (RMSDs) between predicted and 
measured values, suggesting that an assumption of Ttank = 
125[emsp14][deg]F is appropriate. DOE subsequently computed WHAM 
predictions with Ttank assumed down to 110[emsp14][deg]F and 
found that the assumption of Ttank = 125[emsp14][deg]F held 
as the best predictor of measured performance.
    In summary, DOE has found that a disparity between Ttank 
and Tdel exists but not to the extent that commenters have 
stated. Further, using Ttank values below 125[emsp14][deg]F 
within the WHAM model does not result in a better prediction of 
performance. Therefore, DOE continues to propose an assumed average 
tank temperature of 125[emsp14][deg]F in the WHAM calculations that are 
part of the conversion of EF to UEF.
    Comments were received on DOE's assumption in the WHAM model that 
the recovery efficiency and the UA values do not change from the EF 
test to the UEF test. Bradford White disagreed with the belief that the 
UA and recovery efficiency do not change with the change in storing 
water at 135[emsp14][deg]F versus delivering at 125[emsp14][deg]F. 
(Bradford White, No. 14 at p. 2) NEEA commented that the recovery 
efficiency of heat pump water heaters changes dramatically with 
different stored water temperature and disputed DOE's contention that a 
7-percent change in UA is immaterial to the WHAM calculation. (NEEA, 
No. 15 at p. 3) DOE notes that the WHAM model is not used in the 
conversion that has been proposed for heat pump water heaters (rather 
DOE proposes the conversion derived from empirical regression), so 
NEEA's comment regarding the variation in recovery efficiency of heat 
pump water heaters is not germane to this issue. Lutz suggested a 
different approach for determining the key performance metrics when 
test conditions change from an average stored water temperature of 
135[emsp14][deg]F to an average delivered water temperature of 
125[emsp14][deg]F. (Lutz, No. 16 at pp. 4-6) Lutz recommends an 
approach whereby a thermal standby loss and a conversion efficiency are 
obtained from metrics reported in the EF test, and that these terms are 
used to estimate energy consumption under the UEF test.
    To evaluate these suggestions, DOE first examined test data to 
estimate changes in both UA and recovery efficiency arising from 
changes in test temperature. To remove any variability in these metrics 
arising from changes in the procedures used to compute them, DOE 
focused on a subset of tests in which the same draw pattern and 
calculation procedure were used with the thermostats set according to 
the EF test procedure or the UEF test procedure. By focusing on a 
comparison of recovery efficiency and UA obtained during those two 
tests, effects of the calculation procedure are minimized to allow the 
focus to be placed on changes in tank temperature. It was found that 
the UA of both gas-fired and electric storage water heaters dropped an 
average of 7 percent, with a standard deviation of 3 percent. While it 
was assumed that the recovery efficiency of electric storage water 
heaters stays at 0.98, the recovery efficiency of gas-fired storage 
water heaters was found to increase 2 percent at a delivered 
temperature of 125[emsp14][deg]F compared to a stored water temperature 
of 135[emsp14][deg]F. Given these values, DOE then explored how changes 
in the UA value and recovery efficiency affected overall WHAM 
predictions of the UEF for all water heaters tested. The UA was reduced 
by 7 percent and the recovery efficiency increased 2 percent from their 
values determined in the EF test. Combinations of the different 
settings of UA, recovery efficiency, and Ttank were used (a 
total of 8 in all), and RMSDs were computed. The RMSD was lowest under 
the assumption that the UA and recovery efficiency were the same from 
the EF test to the UEF test. This finding held when all water heaters 
were grouped together, as well as when they were separated by fuel type 
(i.e., electric and gas). While limited testing indicated that reducing 
the set point temperature changed the recovery efficiency and UA 
values, when applied to the entire dataset, the model produced 
predictions with lower RMSDs under the assumption of no change in 
recovery efficiency or UA values.
    DOE also compared predictions from procedures described by Lutz to 
the measured data. DOE found that the RMSD when comparing all water 
heaters was essentially the same as for the WHAM model, with the RMSD 
of the Lutz approach being slightly lower for electric water heaters 
and slightly higher for gas-fired water heaters.
    In summary, DOE found that the WHAM model provided more accurate 
predictions of actual performance when Ttank is assumed to 
be 125[emsp14][deg]F and the values for UA and recovery efficiency are 
assumed identical under both the EF and UEF test procedures. Further, 
when comparing the WHAM and Lutz methods, the RMSDs were found to be 
essentially the same. Therefore, DOE proposes to use as the basis of 
its conversion factors for consumer storage water heaters the WHAM 
model with an

[[Page 59748]]

assumed Ttank = 125[emsp14][deg]F and an assumption that the 
recovery efficiency and UA values are identical under the UEF test, as 
they are under the EF test.
    Rheem commented that the method of deriving the coefficients 
presented in the NOPR to determine the WHAM predictions was not clear, 
and AHRI stated that more information was needed on these coefficients. 
(Rheem, No. 11 at p. 6; AHRI, No. 13 at p. 5) In this SNOPR, DOE is 
presenting more details on the derivation of the equations it is 
proposing for converting from prior metrics to the UEF. Additionally, 
the coefficients are modified from the version provided in the NOPR on 
account of different algebraic approaches. In the equations below, 
variables with a subscript ``N'' refer to the UEF test procedure. 
Variables with a subscript ``C'' refer to the EF test procedure.
    The first step is to express the UEF in terms of the delivered 
thermal energy and the energy consumed:
[GRAPHIC] [TIFF OMITTED] TP30AU16.025


where:
A = [rho]NCp,NVN(Tdel,N-
Tin)
B = Ttank,N-Tamb

    It is assumed that the recovery efficiency and UA values are the 
same for both tests. The density, [rho], is evaluated at the delivery 
temperature, Tdel, and the specific heat, Cp, is 
evaluated at the average of Tdel and the inlet temperature, 
Tin. V is the volume delivered for the particular simulated 
use profile implemented during the UEF test.
    The UEF equation can be rearranged to yield the following form:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.026
    
    The input power is given by the variable P. In this equation, UA is 
unknown, so it must be determined from the EF test. The WHAM equation 
for the energy consumed during the EF test, QC, is:
[GRAPHIC] [TIFF OMITTED] TP30AU16.027

Where:

D = [rho]cCp,cVc(Tdel,c-
Tin)
E = (Ttank,c-Tamb)

    With Qc = D/EF, the equation above for UA can be 
rewritten as:

[[Page 59749]]

[GRAPHIC] [TIFF OMITTED] TP30AU16.028

    The values for these coefficients a, b, c, and d are presented in 
Table III.3.

 Table III.3--Coefficients for the Proposed Analytical UEF Conversion Factor for Consumer Storage Water Heaters
----------------------------------------------------------------------------------------------------------------
                  Draw pattern                           a               b               c               d
----------------------------------------------------------------------------------------------------------------
Very Small......................................        0.250266            57.5        0.039864            67.5
Low.............................................        0.065860            57.5        0.039864            67.5
Medium..........................................        0.045503            57.5        0.039864            67.5
High............................................        0.029794            57.5        0.039864            67.5
----------------------------------------------------------------------------------------------------------------

ii. Consumer Instantaneous Water Heater
    Regarding the analytical method to convert prior represented values 
for consumer instantaneous water heaters to UEF, NEEA argued that 
technology differences can cause complications with analytical methods 
but did not suggest any particular improvements to the methods proposed 
by DOE. (NEEA, No. 15 at p. 6) AHRI stated that the determination of 
N*, which is the number of draws from which heat loss occurs to the 
environment, does not factor in the low-fire testing per the EF test 
procedure nor the changes in the flow rate used for the test. (AHRI, 
No. 8 at p. 3) DOE agrees with AHRI's observation, and is modifying its 
analytical model for consumer instantaneous water heaters accordingly 
to account for this change.
    The loss factor represents the amount of energy stored in the 
materials making up the instantaneous water heater. Its value was 
obtained in the NOPR by examining test data and applying the following 
equation for each test:
[GRAPHIC] [TIFF OMITTED] TP30AU16.029

    In the April 2015 NOPR, DOE indicated that N* is the total number 
of draws during the test scaled with respect to the standby time 
occurring after the draw is completed. 80 FR 20116, 20127 (April 14, 
2015). Those draws that are followed by less than one hour contribute a 
fractional value to N* that is equal to the standby time in minutes 
following the draw divided by 60 minutes, while the draws that are 
followed by one hour or more contribute a value of one to N*. To 
determine the loss factor (LF) from the equation above, data are 
obtained from the EF test, but, as AHRI notes, the N* depends upon the 
length of those six draws in the test. Those draws are of different 
length, with the first three occurring at maximum flow rate and the 
final three occurring at minimum flow rate. Therefore, the value of N* 
will not be constant for all water heaters. Instead, DOE computed a 
separate value of N* for each test based upon reported data on the flow 
rates of each draw. From these flow rates, an estimate of the length of 
each draw was obtained, and the standby time before the next draw could 
be computed. Given this adjusted

[[Page 59750]]

technique, along with additional test data collected since the NOPR, 
DOE computed new loss factors. It found that loss factors were 
different for electric instantaneous water heaters than for gas-fired 
instantaneous water heaters, so it is using different analytical 
equations for gas-fired and electric models. The loss factor, LF, being 
used is 0.592 Btu/[deg]F for gas-fired instantaneous water heaters, and 
LF for electric instantaneous water heaters is 0.084 Btu/[deg]F.
    The loss factor, N* for the new draw patterns of the UEF test, and 
the test conditions imposed in the UEF test are used with the equation 
above to estimate the energy consumed for a particular draw pattern for 
either electric or gas-fired units. The UEF can be determined as:
[GRAPHIC] [TIFF OMITTED] TP30AU16.030

    The energy delivered as hot water, Qdel (= 
[rho]cpV(Tdel-Tin)), and N* depend 
upon the draw pattern. The delivered temperature is assumed to be 
125[emsp14][deg]F, and the ambient temperature is assumed to be 
67.5[emsp14][deg]F. This equation can be rearranged by multiplying the 
numerator and denominator by [eta]r/Qdel, 
resulting in an equation of the form:
[GRAPHIC] [TIFF OMITTED] TP30AU16.031

    Density, [rho], is computed at the delivery temperature of 
125[emsp14][deg]F, and cp is computed at the average of the 
delivery temperature and the inlet temperature, or 91.5[emsp14][deg]F. 
The values for N* and A are provided in Table III.4.

  Table III.4--N* and Coefficients for the Proposed Analytical UEF Conversion Factor for Consumer Instantaneous
                                                  Water Heaters
----------------------------------------------------------------------------------------------------------------
                                                                                                 A
                          Draw pattern                                  N*       -------------------------------
                                                                                     Electric           Gas
----------------------------------------------------------------------------------------------------------------
Very Small......................................................            4.36        0.003819        0.026915
Low.............................................................            6.72        0.001549        0.010917
Medium..........................................................            7.45        0.001186        0.008362
High............................................................            7.53        0.000785        0.005534
----------------------------------------------------------------------------------------------------------------

iii. Residential-Duty Commercial Storage Water Heaters
    Regarding the analytical method to convert standby loss and thermal 
efficiency metrics for residential-duty commercial water heaters to 
UEF, DOE received comments from Rheem, AHRI, and NEEA. NEEA stated that 
there is poor agreement between predictions and measured values and 
indicated that there must be some missing variables or factors, but 
NEEA also commented that it is not clear what those factors might be. 
(NEEA, No. 15 at p. 6) Rheem argued that DOE needs to replace the 
``24'' multiplier with the difference between 24 and the burner on-time 
in the 24-hour testing period to account for the actual time of heat 
loss during the test. (Rheem, No. 11 at p. 6) AHRI commented that UA 
losses only occur when the burner is not firing, so the 24 hours should 
be reduced by the total burner on time over the simulated day. (AHRI, 
No. 13 at p. 7)
    In response to NEEA's comment, DOE has evaluated the factors 
included in the analytical model and has not identified other terms 
that would increase the accuracy of the predictions. In any case, to 
the extent unknown factors are important, the use of regressions on top 
of the analytical approach should account for such factors.
    DOE agrees with the comments from Rheem and AHRI and is modifying 
the analytical equation used to predict UEF for residential-duty water 
heaters to adjust the time of application of standby losses. The new 
equation proposed for estimating the energy consumption of a 
residential-duty commercial water heater as a function of standby loss, 
SL, thermal efficiency, Et, and input power, P, is:

[[Page 59751]]

[GRAPHIC] [TIFF OMITTED] TP30AU16.032

    This equation mirrors the WHAM equation, with the second term in 
the square brackets removing addition of standby loss while the burner 
is operating. This step avoids double counting standby loss, as it is 
already incorporated in the thermal efficiency metric while the burner 
is operating. The equation can be rewritten as:
[GRAPHIC] [TIFF OMITTED] TP30AU16.033

Where A = [rho]cpV(Tdel-Tin) and F 
= (Ttank-Tamb)/70.
    The UEF can be determined as Qdel/Q = A/Q. Substituting 
the equation for Q into this ratio yields:
[GRAPHIC] [TIFF OMITTED] TP30AU16.034

    Further rearranging yields the following expression for UEF:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.035
    
    Where

    G = 24/A. Values for the coefficients F and G are presented in 
Table III.5.

  Table III.5--Coefficients for the Proposed Analytical UEF Conversion
    Factor for the Residential-Duty Commercial Storage Water Heaters
------------------------------------------------------------------------
              Draw pattern                       F               G
------------------------------------------------------------------------
Very Small..............................        0.821429       0.0043520
Low.....................................        0.821429       0.0011450
Medium..................................        0.821429       0.0007914
High....................................        0.821429       0.0005181
------------------------------------------------------------------------

iv. Residential-Duty Commercial Electric Instantaneous Water Heaters
    For the UEF conversion, DOE tentatively concluded that given the 
similarities between consumer electric instantaneous water heaters and 
residential-duty commercial electric instantaneous water heaters, the 
principles used to derive the consumer electric instantaneous 
analytical conversion apply to the residential-duty commercial 
equipment class as well. Therefore, DOE is proposing to use the 
consumer electric instantaneous mathematical conversion as a starting 
point for developing the residential-duty electric instantaneous 
conversion, with the assumption that thermal efficiency is 
approximately equal to recovery efficiency. Using this assumption, DOE 
modified the consumer electric instantaneous analytical equation to the 
form found below, where Et is thermal efficiency and A is 
coefficient found in Table III.4. DOE proposes to use this equation as 
the mathematical conversion factor for residential-duty commercial 
electric instantaneous water heaters.
[GRAPHIC] [TIFF OMITTED] TP30AU16.036

5. Empirical Regression Approach
    As noted, the empirical regression approach does not necessarily 
assume any prior knowledge of water heater performance, so DOE sought 
an approach that would allow it to consider many factors as part of its 
regression equations, but would systematically eliminate any that were 
not shown to have a substantive impact on the resulting performance 
metrics. DOE selected a step regression method to accomplish this goal. 
The step regression method examines a series of linear equations that 
relate the new delivery capacity and UEF to a set of observed 
independent variables, such as storage volume, input rate, EF test 
procedure delivery capacity, recovery efficiency, energy factor, 
thermal efficiency, or standby loss. The step regression method 
systematically recombines the set of independent variables to produce 
an equation for each possible set. Each set's equation is compared to 
the others, and the

[[Page 59752]]

equation with the best fit to the actual data is chosen.
    This approach eliminates factors that are not significant in 
converting from the EF, TE, and SL metrics to the UEF metrics, but 
could yield a ``best'' fit that might be more complicated than a 
simpler equation with a marginally worse level of match to experimental 
data. In addition to making the conversion equations more prone to 
error in implementation, a complicated equation may also include 
factors that would not be applicable to the entire population of water 
heaters. DOE, therefore, also considered simpler regression forms to 
reduce confusion in converting from old metrics to new metrics and to 
ensure that the regressions were applicable over the broad range of 
water heaters available on the market. In these circumstances, DOE 
examined the differences between measured values and predicted values 
from the correction equations. When those differences were comparable 
for two different models, DOE opted for the simpler of the two, so long 
as it captured what would be expected to be the major phenomena that 
would affect the new metrics. The regression tool found in the Analysis 
ToolPak of Microsoft Excel (2010) was used to calculate the equation 
for each set of independent variables.
    In the April 2015 NOPR, DOE noted that it was not aware of an 
analytical method for determining the first-hour rating, and proposed 
to use an empirical regression methodology which DOE believed would be 
more accurate than attempting to develop an analytical method. 80 FR 
20116, 20125-28 (April 14, 2015). As noted previously in section 
III.C.2, DOE did not receive any comments suggesting an alternate 
methodology for determining first-hour rating, and, thus, DOE is 
proposing conversion factors for those metrics and product types based 
on the use of the empirical regression methodology. In addition, for 
heat pump water heaters, DOE found that the conversion equations 
resulting from the analytical method and hybrid regressed-analytical 
approach had higher RMSD values than those resulting from the empirical 
regression approach (see section III.E.2.a.ii). Therefore, as proposed 
in the April 2015 NOPR, DOE is proposing a mathematical conversion for 
heat pump water heaters based on the empirical regression approach. Id. 
at 20132. (However, as discussed in section III.E.2.a.ii, this approach 
was modified based on comments received from interested parties.)

D. Testing Conducted for the Mathematical Conversion

    This section provides an overview of the consumer and residential-
duty commercial water heater markets and the test data that were 
available to DOE when developing the NOPR and SNOPR conversion factors.
    As discussed in the April 2015 NOPR, many stakeholders commented on 
the importance of using actual test data in the derivation of the 
mathematical conversion factor. 80 FR 20116, 20121 (April 14, 2015). 
DOE used actual test data as part of the basis for the conversion 
factors and to validate the results. The models selected for testing in 
the April 2015 NOPR were chosen based on their characteristics being 
generally reflective of the broader market. In response to the April 
2015 NOPR, DOE received comments suggesting areas of the market that 
were not adequately tested. These comments, along with DOE's responses, 
are discussed in detail later in this section.
    For consumer and residential-duty commercial water heaters, DOE 
used the Compliance Certification Management System (CCMS) and 
crosschecked it with the AHRI directory \8\ to determine the 
characteristics of models available on the market. DOE conducted 
additional research into manufacturers' literature to identify 
characteristics related to the water heater performance, such as the 
input capacity (for models not listed in the AHRI directory), venting 
options, tank configuration (short or tall), NOX emissions 
level, ignition type (standing or non-standing pilot), and whether the 
model is certified for use in mobile homes. DOE also used the first-
hour ratings based on the EF test procedure to attempt to predict the 
draw pattern that would result from the UEF test, and considered the 
probable draw pattern when selecting models for testing.\9\ However, 
upon testing the models according to the UEF test method, the predicted 
draw pattern bin and the actual draw pattern bin did not always match 
up, and therefore, the actual number of models tested to each draw 
pattern was different than originally predicted. DOE attempted to test 
water heaters representative of the categories listed above, from 
various manufacturers, and to a similar percentage of the market across 
these categories (e.g., DOE attempted to test approximately 8 percent 
of both the short and tall water heater markets, resulting in more tall 
units being tested due to the tall market being larger). Table III.6 
shows the consumer water heater market distribution by product class, 
and by various attributes that commenters suggested DOE should examine. 
Table III.6 also shows the predicted and actual number of tested water 
heaters, where the predicted draw pattern of the model selected may 
have differed from the actual draw pattern that was used once testing 
was performed. Table III.7 through Table III.12 show the consumer 
market distribution by rated storage volume and input rate for various 
water heater types, along with the number of units tested for the April 
2015 NOPR in each category. Table III.13 shows the market distribution 
for consumer heat pump water heaters by rated storage volume and EF, 
along with the number of units tested for the April 2015 NOPR in each 
category. Table III.14 and Table III.15 show the residential-duty 
commercial water heater market distribution by input rate and rated 
storage volume and the number of units tested for the April 2015 NOPR 
for gas-fired and oil-fired water heaters, respectively. The numbers 
provided below for the market and test distribution are for unique 
basic models, as opposed to individual model numbers, due to the 
addition of AHRI aggregated test data discussed further in this 
section. As discussed in detail immediately below, the following tables 
show the number of models tested for the NOPR. After the NOPR tables, 
are tables containing the additional number of models that DOE used for 
this SNOPR.
---------------------------------------------------------------------------

    \8\ The numbers presented in the following tables are from the 
CCMS directory as of September 2015 and the AHRI directory as of 
July 2015.
    \9\ As compared to the EF test procedure that relies on a single 
draw pattern, the UEF test procedure employs one of four patterns, 
the choice of which is determined based on the result of the first-
hour rating test (for storage water heaters) or the maximum GPM 
rating test (for instantaneous water heaters).

[[Page 59753]]



           Table III.6--Consumer Water Heater Test Data Used in the NOPR and Market Distribution by Product Type and Water Heater Attribute *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           O-S             E-S
                  Water heater type **                        G-S        [dagger]   [dagger][dagger]      HP-S         T-S          G-I          E-I
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total Units.............................................       21/340          2/7           9/105           5/26          2/5       17/139         5/67
Venting Options:
    Atmospheric.........................................       14/240          0/7              --             --           --           --           --
    Power...............................................         7/99           --              --             --           --       17/139           --
Short or Tall:
    Short...............................................         7/94           --            2/39             --           --           --           --
    Tall................................................       14/188          2/7            7/42             --           --           --           --
NOX Emissions:
    Standard............................................         2/70           --              --             --           --           --           --
    Low.................................................       16/199           --              --             --           --         6/33           --
    Ultra-Low...........................................         3/71           --              --             --           --       11/103           --
Ignition:
    Standing Pilot......................................       11/239           --              --             --           --           --           --
    No Standing Pilot...................................       10/100          2/7              --             --           --       12/103           --
Mobile Home Certified:
    No..................................................       21/326          2/7            9/99           5/26          2/5       16/138         5/67
    Yes.................................................         0/14           --             0/6             --           --          1/1           --
Draw Pattern: [dagger][dagger][dagger]
    Very Small..........................................           --           --              --             --           --           --       5/5/67
    Low.................................................        1/0/7           --          1/3/46          0/1/1        2/2/4        1/2/2           --
    Medium..............................................     10/8/161           --          7/6/54         2/3/13        0/0/1       7/8/56           --
    High................................................    10/13/172        1/2/7           0/0/5         1/1/12           --       7/7/81           --
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the actual number of tested units/the number of models available on the market. In the draw pattern
  rows, the first number is the number of tested units that DOE predicted would be in each draw pattern when that unit was selected based on the unit's
  EF test procedure delivery capacity; the second number is the actual number of tested units in each draw pattern; and the third number is the number
  of models available on the market. A ``--'' indicates that there are no models available in the category, and, thus, there were no units tested.
** Each water heater type is abbreviated using a two part designation: For the first letter(s), ``G'' means gas-fired, ``O'' means oil-fired, ``E''
  means electric, ``HP'' means heat pump, and ``T'' means tabletop, and for the second letter ``S'' means storage and ``I'' means instantaneous.
[dagger] Two oil-fired storage water heaters were tested, but only one is compliant with the current energy conservation standards.
[dagger][dagger] This category includes only electric storage water heaters that use electric resistance elements, and does not include electric heat
  pump water heaters.
[dagger][dagger][dagger] First-hour ratings from the EF test procedure were used to estimate draw patterns.


           Table III.7--Consumer Gas-Fired Storage Test Data Used in the NOPR and Market Distribution by Input Rate and Rated Storage Volume *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Rated storage volume  (gallons)
        Input rate (kBtu/h)         --------------------------------------------------------------------------------------------------------------------
                                          20           28           29           30           38           40           48           50           55
--------------------------------------------------------------------------------------------------------------------------------------------------------
30.................................           --     0/1 (0%)           --     0/9 (0%)           --     0/4 (0%)           --           --           --
32.................................           --           --    1/4 (25%)     0/4 (0%)           --     0/3 (0%)           --           --           --
33.................................           --           --           --     0/1 (0%)           --           --           --           --           --
34.................................           --           --           --           --           --     0/7 (0%)           --           --           --
35.................................           --           --           --    0/12 (0%)           --     0/1 (0%)           --           --           --
35.5...............................           --           --           --     0/6 (0%)           --     0/2 (0%)           --           --           --
36.................................           --           --           --           --     0/1 (0%)   1/10 (10%)           --    1/11 (9%)           --
37.................................           --           --           --           --           --     0/1 (0%)           --           --           --
38.................................           --           --           --           --     0/1 (0%)    1/17 (6%)     0/1 (0%)     0/9 (0%)           --
40.................................           --           --           --           --     0/3 (0%)   9/85 (11%)    1/4 (25%)    1/71 (1%)           --
42.................................           --           --           --           --           --     0/5 (0%)           --     0/8 (0%)           --
45.................................           --           --           --           --           --           --     0/1 (0%)    1/3 (33%)     0/2 (0%)
47.................................           --           --           --           --           --           --           --    1/3 (33%)           --
48.................................           --           --           --           --           --           --     0/1 (0%)           --           --
50.................................           --           --           --           --           --     0/2 (0%)     0/1 (0%)    1/8 (13%)     0/2 (0%)
55.................................           --           --           --           --           --           --     0/1 (0%)           --           --
56.................................           --           --           --           --           --           --     0/2 (0%)           --           --
58.................................           --           --           --           --           --           --           --     0/1 (0%)           --
60.................................           --           --   1/1 (100%)           --           --           --     0/5 (0%)     0/9 (0%)     0/2 (0%)
62.................................           --           --           --           --           --           --           --     0/6 (0%)           --
65.................................           --           --           --           --           --           --     0/5 (0%)    1/3 (33%)           --
75.................................     0/1 (0%)           --           --           --           --           --           --           --           --
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the market. The percentage of models tested
  is in parentheses below the counts of units tested and models. A ``--'' indicates that there are no models available in the category, and, thus, there
  were no units tested.


[[Page 59754]]


  Table III.8--Consumer Electric Storage Test Data Used in the NOPR and
      Market Distribution by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All input
             Rated storage volume  (gallons)                   rates
------------------------------------------------------------------------
28......................................................        0/6 (0%)
30......................................................       1/27 (4%)
36......................................................        0/1 (0%)
38......................................................        0/6 (0%)
40......................................................      4/29 (14%)
47......................................................        0/2 (0%)
50......................................................      3/26 (12%)
52......................................................        0/2 (0%)
55......................................................       1/6 (17%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


Table III.9--Consumer Gas-Fired Instantaneous Test Data Used in the NOPR
    and Market Distribution by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All rated
                   Input rate (kBtu/h)                        storage
                                                              volumes
------------------------------------------------------------------------
120.....................................................       1/11 (9%)
130.....................................................        0/2 (0%)
140.....................................................       2/9 (22%)
145.....................................................        0/1 (0%)
150.....................................................       1/13 (8%)
152.....................................................      1/1 (100%)
157.....................................................        0/7 (0%)
160.....................................................        0/6 (0%)
175.....................................................       1/2 (50%)
180.....................................................      3/30 (10%)
190.....................................................       1/9 (11%)
192.....................................................        0/1 (0%)
195.....................................................        0/1 (0%)
199.....................................................       1/27 (4%)
199.9...................................................       2/6 (33%)
200.....................................................      2/13 (15%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


  Table III.10--Consumer Electric Instantaneous Test Data Used for the
  NOPR and Market Distribution by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All rated
                     Input rate (kW)                          storage
                                                              volumes
------------------------------------------------------------------------
2.4.....................................................       1/2 (50%)
3.......................................................        0/6 (0%)
3.4.....................................................        0/1 (0%)
3.5.....................................................        0/9 (0%)
4.1.....................................................        0/3 (0%)
4.8.....................................................        0/5 (0%)
5.5.....................................................        0/2 (0%)
6.......................................................       1/4 (25%)
6.5.....................................................        0/5 (0%)
7.2.....................................................        0/1 (0%)
7.5.....................................................        0/3 (0%)
8.......................................................       1/3 (33%)
8.3.....................................................        0/3 (0%)
9.......................................................        0/3 (0%)
9.5.....................................................       1/6 (17%)
10......................................................       1/4 (25%)
11......................................................        0/2 (0%)
11.5....................................................        0/3 (0%)
12......................................................        0/2 (0%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


 Table III.11--Consumer Tabletop Storage Test Data Used in the NOPR and
      Market Distribution by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All input
             Rated storage volume  (gallons)                   rates
------------------------------------------------------------------------
27......................................................       1/2 (50%)
38......................................................      1/1 (100%)
40......................................................        0/2 (0%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


  Table III.12--Consumer Oil-fired Storage Test Data Used in the NOPR and Market Distribution by Input Rate and
                                             Rated Storage Volume *
----------------------------------------------------------------------------------------------------------------
                                                                          Rated storage volume  (gallons)
                       Input rate (kBtu/h)                       -----------------------------------------------
                                                                        30              32              50
----------------------------------------------------------------------------------------------------------------
90..............................................................              --        0/2 (0%)              --
104.............................................................              --       1/2 (50%)              --
105.............................................................        0/2 (0%)              --        0/1 (0%)
----------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the
  market. The percentage of models tested is in parentheses next to the counts of units tested and models.


                       Table III.13--Consumer Heat Pump Distribution Used for the NOPR by Energy Factor and Rated Storage Volume *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Rated storage volume  (gallons)
                  Energy factor                  -------------------------------------------------------------------------------------------------------
                                                       45           50           58           65           66           72           80          119
--------------------------------------------------------------------------------------------------------------------------------------------------------
2.2.............................................           --   1/1 (100%)           --           --           --           --           --           --
2.21............................................           --           --           --           --           --           --           --     0/1 (0%)
2.31............................................           --           --           --     0/1 (0%)           --           --     0/1 (0%)           --
2.32............................................           --     0/1 (0%)           --           --           --           --           --           --
2.33............................................           --           --           --           --           --           --   1/1 (100%)           --
2.4.............................................           --     0/1 (0%)           --           --           --           --           --           --

[[Page 59755]]

 
2.45............................................     0/1 (0%)    1/2 (50%)           --           --           --     0/1 (0%)     0/1 (0%)           --
2.5.............................................           --           --           --           --     0/1 (0%)           --     0/1 (0%)           --
2.72............................................           --           --           --           --           --           --     0/1 (0%)           --
2.74............................................           --           --           --           --     0/1 (0%)           --           --           --
2.75............................................           --     0/1 (0%)           --           --           --           --           --           --
2.9.............................................           --     0/1 (0%)           --           --           --           --     0/1 (0%)           --
3.05............................................           --           --     0/1 (0%)           --           --           --           --           --
3.07............................................           --           --           --           --           --           --     0/1 (0%)           --
3.1.............................................           --     0/1 (0%)           --           --           --           --     0/1 (0%)           --
3.17............................................           --           --           --           --     0/1 (0%)           --           --           --
3.24............................................           --     0/1 (0%)           --           --           --           --           --           --
3.39............................................           --           --           --           --           --           --     0/1 (0%)           --
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the market. The percentage of models tested
  is in parentheses below the counts of units tested and models. A ``--'' indicates that there are no models available in the category, and, thus, there
  were no units tested.


  Table III.14--Residential-Duty Commercial Gas-fired Storage Test Data Used in the NOPR and Market Distribution by Input Rate and Rated Storage Volume
                                                                         *\,\**
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Rated storage volume  (gallons)
      Input rate (kBtu/h)       ------------------------------------------------------------------------------------------------------------------------
                                     34         40         50         55         60         74         75         80         98        100        119
--------------------------------------------------------------------------------------------------------------------------------------------------------
75.............................         --         --         --         --         --         --   0/1 (0%)         --         --         --         --
75.1...........................         --         --         --         --         --   0/3 (0%)   0/3 (0%)         --   0/2 (0%)   0/1 (0%)         --
76.............................         --         --  2/4 (50%)         --   0/2 (0%)         --       2/21   0/2 (0%)         --   0/3 (0%)         --
                                                                                                       (10%)
78.............................         --         --         --   0/1 (0%)         --         --         --         --         --         --         --
80.............................         --         --         --   0/2 (0%)         --   0/1 (0%)   0/1 (0%)         --         --        1/1         --
                                                                                                                                       (100%)
85.............................         --         --         --         --         --         --         --         --         --   0/3 (0%)         --
88.............................         --         --         --         --         --         --         --         --         --   0/3 (0%)         --
90.............................         --         --         --         --         --         --         --         --   0/1 (0%)         --         --
91.3...........................         --   0/1 (0%)         --         --         --         --         --         --         --         --         --
98.............................         --         --   0/2 (0%)         --         --         --         --         --         --         --         --
100............................   0/1 (0%)         --   0/1 (0%)   0/3 (0%)         --         --   0/2 (0%)   0/2 (0%)         --         --   0/2 (0%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the market. The percentage of models tested
  is in parentheses below the counts of units tested and models. A ``--'' indicates that there are no models available in the category, and, thus, there
  were no units tested.
** Seven data points were presented in the April 2015 NOPR, but two units were of the same basic model, and three units were tested to the incorrect
  input rate. DOE has removed these data points from the analysis.


 Table III.15--Residential-Duty Commercial Oil-fired Storage Test Data Used in the NOPR and Market Distribution
                                  by Input Rate and Rated Storage Volume *\,\**
----------------------------------------------------------------------------------------------------------------
                                                                          Rated storage volume  (gallons)
                       Input rate (kBtu/h)                       -----------------------------------------------
                                                                        30              50              70
----------------------------------------------------------------------------------------------------------------
119.............................................................        0/2 (0%)        0/1 (0%)        0/1 (0%)
140.............................................................              --        0/1 (0%)              --
----------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the
  market. The percentage of models tested is in parentheses below the counts of units tested and models. A ``--
  '' indicates that there are no models available in the category, and, thus, there were no units tested.

    In addition, AHRI submitted test results for testing conducted 
under both the EF and UEF test methods by its member manufacturers. 
(AHRI, No. 9) As using additional data points will generally reduce the 
uncertainty in the statistical modeling used to generate the conversion 
factor, DOE has incorporated the test data submitted by AHRI in its 
analysis for this SNOPR. DOE also conducted additional testing, which 
was completed after the publication of the April 2015 NOPR, and is 
including the results in this SNOPR. Table III.16 shows the consumer 
market distribution by product class and attributes that commenters 
suggested DOE examine, along with the number of units tested for the 
development of this SNOPR in each category. Table III.17 through Table 
III.21 show the consumer market

[[Page 59756]]

distribution by rated storage volume and input rate for various water 
heater categories and the number of units tested for this SNOPR in each 
category. Table III.22 shows the consumer heat pump market distribution 
by rated storage volume and EF and the number of units tested for this 
SNOPR in each category. Table III.23 and Table III.24 show the 
residential-duty commercial market distribution by input rate and rated 
storage volume and the number of units tested for this SNOPR in each 
category. AHRI did not supply model numbers in its data, so some 
percentages in the tables below are greater than 100 percent, 
suggesting that DOE and AHRI have data on the same water heaters. Both 
the DOE and AHRI data sets contain some test points that are from 
different water heaters of the same model. These models were only 
counted once in the tables below, and the test data were averaged into 
a single data point in the conversion factor derivation.

                Table III.16--Consumer Market Distribution and Test Data Used for this SNOPR by Product Type and Water Heater Attribute*
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           O-S             E-S
                  Water heater type **                        G-S        [dagger]   [dagger][dagger]      HP-S         T-S          G-I          E-I
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total Units.............................................      118/340          2/7          46/105          16/26          3/5       53/139         5/67
Venting Options
    Atmospheric.........................................       84/240          0/7              --             --           --           --           --
    Power...............................................        33/99           --              --             --           --       53/139           --
Short or Tall
    Short...............................................        42/94           --           11/39             --           --           --           --
    Tall................................................       75/188          2/7           19/42             --           --           --           --
NOX Emissions
    Standard............................................        13/70           --              --             --           --           --           --
    Low.................................................       81/199           --              --             --           --         9/33           --
    Ultra-Low...........................................        24/71           --              --             --           --       44/103           --
Ignition
    Standing Pilot......................................       76/239           --              --             --           --           --
    No Standing Pilot...................................       41/100          2/7              --             --           --       48/103           --
Mobile Home Certified
    No..................................................      118/326          2/7           46/99          16/26          3/5       52/138         5/67
    Yes.................................................         0/14           --             0/6             --           --          1/1           --
Draw Pattern [dagger][dagger][dagger]
    Very Small..........................................           --           --              --             --           --           --       5/5/67
    Low.................................................        4/2/7           --        12/13/46          0/1/1        3/2/4        1/2/2           --
    Medium..............................................    55/55/161           --        31/32/54         7/9/13        0/1/1     13/21/56           --
    High................................................    59/61/172        1/2/7           4/1/5         6/6/12           --     18/30/81           --
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the actual number of tested units/the number of models available on the market. In the draw pattern
  rows, the first number is the number of tested units that DOE predicted would be in each draw pattern when that unit was selected based on the unit's
  EF test procedure delivery capacity; the second number is the actual number of tested units in each draw pattern; and the third number is the number
  of models available on the market. A ``--'' indicates that there are no models available in the category, and, thus, there were no units tested.
** Each water heater type is abbreviated using a two part designation: For the first letter(s) ``G'' means gas-fired, ``O'' means oil-fired, ``E'' means
  electric, ``HP'' means heat pump, and ``T'' means tabletop, and for the second letter ``S'' means storage and ``I'' means instantaneous.
[dagger] Two oil-fired storage water heaters were tested, but only one is compliant with the current energy conservation standards.
[dagger][dagger] In this table, this category includes only electric storage water heaters that use electric resistance elements, and does not include
  electric heat pump water heaters.
[dagger][dagger] First-hour ratings from the EF test procedure were used to estimate draw patterns.


            Table III.17--Consumer Gas-fired Storage Distribution and Test Data Used for This SNOPR by Input Rate and Rated Storage Volume *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Rated storage volume  (gallons)
        Input rate  (kBtu/h)        --------------------------------------------------------------------------------------------------------------------
                                          20           28           29           30           38           40           48           50           55
--------------------------------------------------------------------------------------------------------------------------------------------------------
30.................................           --   1/1 (100%)           --    6/9 (67%)           --    1/4 (25%)           --           --           --
32.................................           --           --    2/4 (50%)    3/4 (75%)           --     0/3 (0%)           --           --           --
33.................................           --           --           --   1/1 (100%)           --           --           --           --           --
34.................................           --           --           --           --           --    3/7 (43%)           --           --           --
35.................................           --           --           --    0/12 (0%)           --     0/1 (0%)           --           --           --
35.5...............................           --           --           --    2/6 (33%)           --     0/2 (0%)           --           --           --
36.................................           --           --           --           --   1/1 (100%)   4/10 (40%)           --   3/11 (27%)           --
37.................................           --           --           --           --           --     0/1 (0%)           --           --           --
38.................................           --           --           --           --     0/1 (0%)   8/17 (47%)     0/1 (0%)    5/9 (56%)           --
40.................................           --           --           --           --    1/3 (33%)  29/85 (34%)    3/4 (75%)  24/71 (34%)           --
42.................................           --           --           --           --           --     0/5 (0%)           --    3/8 (38%)           --
45.................................           --           --           --           --           --           --     0/1 (0%)    2/3 (67%)    1/2 (50%)
47.................................           --           --           --           --           --           --           --    1/3 (33%)           --
48.................................           --           --           --           --           --           --     0/1 (0%)           --           --
50.................................           --           --           --           --           --     0/2 (0%)   1/1 (100%)    3/8 (38%)    1/2 (50%)
55.................................           --           --           --           --           --           --     0/1 (0%)           --           --
56.................................           --           --           --           --           --           --     0/2 (0%)           --           --
58.................................           --           --           --           --           --           --           --     0/1 (0%)           --

[[Page 59757]]

 
60.................................           --           --   2/1 (200%)           --           --           --    1/5 (20%)     0/9 (0%)     0/2 (0%)
62.................................           --           --           --           --           --           --           --    1/6 (17%)           --
65.................................           --           --           --           --           --           --    2/5 (40%)    2/3 (67%)           --
75.................................     0/1 (0%)           --           --           --           --           --           --           --           --
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the market. The percentage of models tested
  is in parentheses below the counts of units tested and models. A ``--'' indicates that there are no models available in the category, and, thus, there
  were no units tested.


 Table III.18--Consumer Electric Storage Distribution and Test Data Used
         for This SNOPR by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All input
             Rated storage volume (gallons)                    rates
------------------------------------------------------------------------
28......................................................       5/6 (83%)
30......................................................      6/27 (22%)
36......................................................        0/1 (0%)
38......................................................       2/6 (33%)
40......................................................     12/29 (41%)
47......................................................        0/2 (0%)
50......................................................     15/26 (58%)
52......................................................       1/2 (50%)
55......................................................       4/6 (67%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


Table III.19--Consumer Gas-Fired Storage Distribution and Test Data Used
         for This SNOPR by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All rated
                   Input rate (kBtu/h)                        storage
                                                              volumes
------------------------------------------------------------------------
120.....................................................      4/11 (36%)
130.....................................................        0/2 (0%)
140.....................................................       5/9 (56%)
145.....................................................        0/1 (0%)
150.....................................................      4/13 (31%)
152.....................................................      3/1 (300%)
157.....................................................       2/7 (29%)
160.....................................................        0/6 (0%)
175.....................................................       1/2 (50%)
180.....................................................      9/30 (30%)
190.....................................................       5/9 (56%)
192.....................................................        0/1 (0%)
195.....................................................        0/1 (0%)
199.....................................................      6/27 (22%)
199.9...................................................     10/6 (167%)
200.....................................................      2/13 (15%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


 Table III.20--Consumer Tabletop Storage Distribution and Test Data Used
         for This SNOPR by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------
                                                             All input
             Rated storage volume  (gallons)                   rates
------------------------------------------------------------------------
27......................................................       1/2 (50%)
38......................................................      1/1 (100%)
40......................................................       1/2 (50%)
------------------------------------------------------------------------
* The information in this table is presented as the number of tested
  units/the number of models available on the market. The percentage of
  models tested is in parentheses next to the counts of units tested and
  models.


 Table III.21--Consumer Oil-Fired Storage Distribution and Test Data Used for This SNOPR by Input Rate and Rated
                                                Storage Volume *
----------------------------------------------------------------------------------------------------------------
                                                                          Rated storage volume (gallons)
                       Input rate (kBtu/h)                       -----------------------------------------------
                                                                        30              32              50
----------------------------------------------------------------------------------------------------------------
90..............................................................  ..............        0/2 (0%)  ..............
104.............................................................  ..............       1/2 (50%)  ..............
105.............................................................        0/2 (0%)  ..............        0/1 (0%)
----------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the
  market. The percentage of models tested is in parentheses next to the counts of units tested and models.


               Table III.22--Consumer Heat Pump Distribution and Test Data Used for This SNOPR by Energy Factor and Rated Storage Volume *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Rated storage volume (gallons)
                      Energy factor                      -----------------------------------------------------------------------------------------------
                                                              45          50          58          65          66          72          80          119
--------------------------------------------------------------------------------------------------------------------------------------------------------
2.2.....................................................          --  1/1 (100%)          --          --          --          --          --          --
2.21....................................................          --          --          --          --          --          --          --  1/1 (100%)
2.31....................................................          --          --          --  1/1 (100%)          --          --  1/1 (100%)          --
2.32....................................................          --    0/1 (0%)          --          --          --          --          --          --
2.33....................................................          --          --          --          --          --          --  2/1 (200%)          --

[[Page 59758]]

 
2.4.....................................................          --  2/1 (200%)          --          --          --          --          --          --
2.45....................................................    0/1 (0%)   1/2 (50%)          --          --          --    0/1 (0%)    0/1 (0%)          --
2.5.....................................................          --          --          --          --    0/1 (0%)          --    0/1 (0%)          --
2.72....................................................          --          --          --          --          --          --  1/1 (100%)          --
2.74....................................................          --          --          --          --    0/1 (0%)          --          --          --
2.75....................................................          --    0/1 (0%)          --          --          --          --          --          --
2.9.....................................................          --  1/1 (100%)          --          --          --          --  1/1 (100%)          --
3.05....................................................          --          --    0/1 (0%)          --          --          --          --          --
3.07....................................................          --          --          --          --          --          --    0/1 (0%)          --
3.1.....................................................          --    0/1 (0%)          --          --          --          --  1/1 (100%)          --
3.17....................................................          --          --          --          --    0/1 (0%)          --          --          --
3.24....................................................          --    0/1 (0%)          --          --          --          --          --          --
3.39....................................................          --      1/0 **          --          --          --          --    0/1 (0%)          --
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the market. The percentage of models tested
  is in parentheses below the counts of units tested and models. A ``--'' indicates that there are no models available in the category, and, thus, there
  were no units tested.
** AHRI supplied data for this model which is not contained in the version of the CCMS and AHRI databases used for this SNOPR. Due to the high rated EF,
  DOE believes this unit to have recently come on to the market.


                   Table III.23--Residential-Duty Commercial Gas-Fired Storage Test Data Used for This SNOPR and Market Distribution by Input Rate and Rated Storage Volume *
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                Rated storage volume (gallons)
                     Input rate (kBtu/h)                     -----------------------------------------------------------------------------------------------------------------------------------
                                                                  34          40          50          55          60          74          75          80          98          100         119
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
75..........................................................          --          --          --          --          --          --    0/1 (0%)          --          --          --          --
75.1........................................................          --          --          --          --          --   2/3 (67%)   1/3 (33%)          --  3/2 (150%)    0/1 (0%)          --
76..........................................................          --          --  6/4 (150%)          --    0/2 (0%)          --  2/21 (10%)    0/2 (0%)          --    0/3 (0%)          --
78..........................................................          --          --          --    0/1 (0%)          --          --          --          --          --          --          --
80..........................................................          --          --          --    0/2 (0%)          --    0/1 (0%)  1/1 (100%)          --          --  1/1 (100%)          --
85..........................................................          --          --          --          --          --          --          --          --          --   1/3 (33%)          --
88..........................................................          --          --          --          --          --          --          --          --          --    0/3 (0%)          --
90..........................................................          --          --          --          --          --          --          --          --    0/1 (0%)          --          --
91.3........................................................          --    0/1 (0%)          --          --          --          --          --          --          --          --          --
98..........................................................          --          --    0/2 (0%)          --          --          --          --          --          --          --          --
100.........................................................    0/1 (0%)          --  1/1 (100%)    0/3 (0%)          --          --   1/2 (50%)    0/2 (0%)          --          --    0/2 (0%)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the market. The percentage of models tested is in parentheses below the counts of
  units tested and models. A ``--'' indicates that there are no models available in the category, and, thus, there were no units tested.


      Table III.24--Residential-Duty Commercial Oil-Fired Storage Test Data Used for This SNOPR and Market
                              Distribution by Input Rate and Rated Storage Volume *
----------------------------------------------------------------------------------------------------------------
                                                                          Rated storage volume (gallons)
                       Input rate (kBtu/h)                       -----------------------------------------------
                                                                        30              50              70
----------------------------------------------------------------------------------------------------------------
119.............................................................        0/2 (0%)        0/1 (0%)        0/1 (0%)
140.............................................................              --      1/1 (100%)              --
----------------------------------------------------------------------------------------------------------------
* The information in this table is presented as the number of tested units/the number of models available on the
  market. The percentage of models tested is in parentheses below the counts of units tested and models. A ``--
  '' indicates that there are no models available in the category, and, thus, there were no units tested.

    As noted above, DOE received a number of comments suggesting types 
of water heaters for which the commenters said DOE should incorporate 
additional data for the development of the conversion factors. 
Specifically, AHRI and Rheem stated that more short units should be 
tested and in particular, electric short units. (AHRI, No. 13 at p. 5; 
Rheem, No. 11 at p. 7) For the SNOPR, the percentage of gas-fired and 
electric short water heater models on the market that have been tested 
has increased from 7 percent to 45 percent and from 5 percent to 28 
percent, respectively, as compared to the April 2015 NOPR. DOE notes 
that these percentages are based on identification in manufacturer 
literature, as there is no consistent, objective criteria for 
identifying short and tall models across manufacturers. DOE believes 
that the models tested are representative of ``short'' models available 
on the market.
    AHRI stated that units subject to the low draw pattern for the 
consumer electric storage category were not adequately tested. (AHRI, 
No. 13 at p. 5) Rheem also stated that not enough consumer electric 
storage units were tested, but that more testing for the high-draw-
pattern category was needed. (Rheem, No. 13 at p. 7) As noted above,

[[Page 59759]]

the draw pattern classification for DOE's test unit selection was based 
upon the first-hour ratings based on the EF test procedure, as the 
first-hour ratings under the UEF test procedure are not readily 
available in published literature. However, the actual draw pattern for 
each unit tested was found experimentally through testing for the 
first-hour rating under the UEF test method prior to conducting the UEF 
simulated-use test. For the SNOPR, the percentage of electric low- and 
high-draw-pattern water heaters on the market that have been tested has 
increased from 7 percent to 28 percent and from 0 percent to 20 
percent, respectively. These percentages are based on the number of 
units that were determined through testing to be in a draw pattern bin 
as compared to the number of models that would be predicted to be in 
that draw pattern bin.
    Rheem stated that no low-draw-pattern consumer gas-fired water 
heaters were tested. (Rheem, No. 13 at p. 7) DOE predicted seven of the 
340 (i.e., 2.1 percent) gas-fired water heater models on the market to 
be in the low-draw-pattern bin based on their EF test procedure first-
hour rating. For the NOPR, one unit was tested with an expected low-
draw-pattern based on its first-hour rating under the EF test 
procedure, but that unit's tested first-hour rating under the new UEF 
procedure placed it into the medium-draw-pattern bin. Subsequently, two 
consumer gas-fired water heaters were supplied in the AHRI dataset and 
tested to the low-draw-pattern bin under the UEF first-hour rating 
test. Therefore, two low-draw-pattern tests are now available and were 
included in the analysis.
    Rheem stated that there were no tests of consumer gas-fired storage 
water heaters above 55 gallons. (Rheem, No. 13 at p. 7) In response, 
DOE notes that as of the time of this analysis, there are no water 
heaters on the market which would fall into this category.
    AHRI and Rheem suggested that more ultra-low NOX units 
should be tested. (AHRI, No. 13 at p. 5; Rheem, No. 11 at p. 7) For the 
SNOPR, the percentage of ultra-low NOX gas-fired water 
heaters on the market that have been tested has increased from 4 
percent to 34 percent.
    AHRI, GE, and Rheem suggested that more high-EF heat pump units 
should be tested. (AHRI, No. 8 at p. 4; GE, No. 12 at p. 1; Rheem, No. 
11 at p. 7) For the SNOPR, the percentage of high-EF (i.e., EF greater 
than 2.7) heat pump water heaters on the market that have been tested 
has increased from 0 percent to 42 percent.
    AHRI and Rheem commented that the sample size for the residential-
duty gas-fired storage category was too small. (AHRI, No. 13 at p. 6; 
Rheem, No. 11 at p. 7) AHRI and Rheem also stated that no residential-
duty units in the high-input range were tested. (AHRI, No. 8 at p. 4; 
Rheem, No. 11 at p. 7) For the SNOPR, the percentage of residential-
duty commercial gas-fired storage water heaters on the market that have 
been tested has increased from 7 percent to 28 percent, and the 
percentage of high-input (i.e., input rate greater than 90,000 Btu/h) 
units has increased from 0 percent to 14 percent.
1. Repeatability
    In response to the April 2015 NOPR, commenters stated that the 
repeatability of the UEF test procedure was not analyzed. (AHRI, No. 8 
at p. 5; Rheem, No. 11 at p. 6) In response, DOE acknowledges that each 
water heater was tested once, and repeat tests of the same unit were 
not conducted by DOE. During its test procedure rulemaking to establish 
the UEF test method, stakeholders did not raise concerns regarding 
repeatability, and, therefore, DOE did not specifically evaluate this 
issue during testing conducted for the NOPR. However, AHRI submitted 
data that appears to show the variations in the experimental results 
from testing a given unit are unlikely to contribute more than a de 
minimis amount of uncertainty to the overall regression. One consumer 
electric storage water heater (Test ID No. 1-61 and 1-62) and one 
consumer gas-fired instantaneous water heater (Test ID No. 1-83 and 1-
84) were tested multiple times. For the consumer electric storage water 
heater, the only difference between the two tests was the result of the 
EF test procedure's first-hour rating test (difference of 3 gallons). 
For the gas-fired instantaneous water heater, the differences in the EF 
test procedure maximum GPM, EF, UEF test procedure maximum GPM, and UEF 
results were 0.019 gpm, 0.0017, 0.0002 gpm, and 0.0012, respectively. 
(AHRI, No. 9 Attachment) These data suggest that the EF and UEF test 
procedures are repeatable.
    For this SNOPR, DOE conducted additional testing that allowed DOE 
to further examine the repeatability of the test method. DOE tested 
eight units, two different units of one model and 3 different units of 
2 other models. Because the different units may have slightly different 
EF or UEF characteristics, the variability in these results is an upper 
bound for the variability introduced by the test methods themselves. 
The variability was similar for all three, and DOE has no reason to 
think the test methods would produce significantly different levels of 
variability for other types of water heaters. The results of the 
testing are shown in Table III.25. The standard deviations of the EF 
and UEF tests for models 1, 2, and 3 are 0.0018 and 0.0035, 0.0033 and 
0.0044, and 0.0149 and 0.0116, respectively. These standard deviations 
are all within the same magnitude for each model and for the case of 
model 3 the UEF standard deviation is less than EF. The results 
indicate a reasonable level of repeatability in the test procedure.

                   Table III.25--Results for Repeatability Testing for EF and UEF Test Methods
----------------------------------------------------------------------------------------------------------------
                      Model                            Unit          Rated EF        Tested EF      Tested UEF
----------------------------------------------------------------------------------------------------------------
1...............................................               1            0.95           0.947            .949
1...............................................               2            0.95           0.949            .944
2...............................................               1            0.95           0.937            .903
2...............................................               2            0.95           0.940            .909
2...............................................               3            0.95           0.934            .901
3...............................................               1            0.95           0.908            .914
3...............................................               2            0.95           0.932            .898
3...............................................               3            0.95           0.905            .892
----------------------------------------------------------------------------------------------------------------


[[Page 59760]]

E. Testing Results and Analysis of Test Data

1. Impact of Certain Water Heater Attributes on Efficiency Ratings
    After conducting testing on all of the selected water heaters 
according to both the prior test procedures and the uniform efficiency 
descriptor test procedure, DOE examined how particular attributes of 
water heaters might affect the conversion factors and investigated the 
approaches discussed in section III.C for obtaining conversion factors. 
The goal of this analysis was to determine whether or not particular 
attributes would warrant separate conversion equations. DOE 
investigated attributes such as: (1) NOX emission level; (2) 
short or tall configuration; (3) vent type; (4) standing pilot versus 
electronic ignition; (5) whether condensing or heat pump technology is 
used; and (6) whether the unit is tabletop. The RMSD between the 
measured values and the values obtained through various conversion 
methods was compared. The conversion approach with the lowest 
cumulative RMSD value for a particular fuel type was considered to be 
the best candidate for the conversion equation.
    In the April 2015 NOPR, DOE proposed to adopt different conversion 
equations based on the level of NOX emissions. 80 FR 20116, 
20129-30 (April 14, 2015). The three levels of NOX emissions 
currently available in water heaters on the market include standard 
(greater than or equal to 40 nanograms per joule (ng/J)), low (less 
than 40 ng/J and greater than or equal to 10 ng/J for storage water 
heaters, and less than 40 ng/J and greater than or equal to 14 ng/J for 
instantaneous water heaters), and ultra-low (less than 10 ng/J for 
storage water heaters and less than 14 ng/J for instantaneous water 
heaters). AHRI commented that separate conversions for standard and 
low-NOX water heaters are not needed. (AHRI, No. 8 at p. 4) 
As a result, DOE re-examined the data to determine the variability of 
the conversions when considering standard and low-NOX water 
heaters together, and separately from ultra-low-NOX water 
heaters. DOE found that the combined approach recommended by AHRI 
slightly reduces the variability of the conversion equations, and, 
thus, the Department has included standard and low-NOX water 
heaters in a single set of conversion equations in this supplemental 
proposal. The proposal continues to treat ultra-low-NOX 
water heaters separately, because an ultra-low-NOX burner 
has a fundamentally different design than standard and low-
NOX burners and the resulting RMSD values are lower for each 
category when separated.
    Most units that are short or tall have been labeled as such by the 
manufacturer; however, some units do not have this designation. DOE has 
found that some units labeled as ``short'' are actually taller than 
units labeled as ``tall.'' In the NOPR, DOE requested comment on how 
manufacturers determine whether a unit is short or tall. 80 FR 20116, 
20129 (April 14, 2015). No response was received related to this 
inquiry, so DOE considered manufacturer literature in determining 
whether a model was ``tall'' or ``short,'' although as noted, the 
criteria for classification was not always consistent across 
manufacturers. DOE examined separate conversions for tall and short 
water heaters based on their identification in manufacturer literature; 
however, DOE ultimately did not propose separate conversions because it 
did not yield materially different results and is not based on discrete 
design characteristics that are consistent across all manufacturers.
    As explained in the April 2015 NOPR, the four venting 
configurations currently available in water heaters on the market 
include atmospheric, direct, power, and power-direct. Atmospheric and 
power vent units intake air from the area surrounding the water heater, 
while direct and power-direct vents intake air from outdoors. 
Atmospheric and direct vent units use natural convection to circulate 
combustion air, while power and power-direct vents use some additional 
method to force circulation of combustion air. Concentric inlet and 
outlet piping is a configuration that can be used in directly venting 
water heaters to preheat incoming air using exhaust gas. For these 
tests, concentric inlet and outlet piping was not used; inlet air for 
the direct and power-direct vent units was delivered to the water 
heater in separate pipes from that used for exhaust. As these tests 
were conducted under identical controlled conditions, DOE determined 
that there is very little difference, in terms of the comparison 
between EF and UEF, between atmospheric and direct vent water heaters 
and also between power and power-direct vent. For these reasons DOE 
grouped atmospheric and direct into the atmospheric configuration and 
power and power-direct into the power configuration. Similarly, DOE 
determined that there was not a significant difference between 
electronic ignition and standing pilot units and grouped those together 
for this conversion. 80 FR 20116, 20129-30 (April 14, 2015).
    Rheem commented that DOE should test ultra-low-NOX 
consumer gas-fired storage water heaters that use a power vent to 
determine whether a different UEF conversion factor is warranted to 
differentiate between the different vent types of ultra-low-
NOX water heaters. (Rheem, No. 11 at p. 7) AHRI submitted 
test data for 17 ultra-low-NOX consumer gas-fired water 
heaters: 9 that are atmospherically vented and 8 that are power vented. 
DOE analyzed separating the ultra-low-NOX consumer gas-fired 
storage category into atmospherically vented and power vented 
categories, and found that the RMSD value decreased by less than 0.001 
when separated. DOE tentatively considers a change in RMSD to be 
negligible if it is less than one unit (0.01 for EF and UEF, 0.1 for 
maximum GPM, and 1.0 for first-hour rating). DOE has tentatively 
decided that this decrease is not significant enough to justify a 
separate conversion, given the additional complexity of separating 
these products by vent type.
    In the April 2015 NOPR, DOE tentatively concluded that tabletop 
units were not significantly different from electric resistance storage 
water heaters and considered them together for the purposes of 
developing the mathematical conversion. 80 FR 20116, 20132 (April 14, 
2015). Upon further consideration, DOE believes that tabletop units, 
due to their efficiency ratings being well below those of traditional 
electric storage water heaters, may react differently to the UEF test 
procedure than traditional electric storage water heaters. Therefore, 
DOE has tentatively decided to propose separate conversions for 
tabletop and electric resistance water heaters in this SNOPR.
2. Conversion Factor Derivation
    DOE used the methods described in section III.C to derive the 
mathematical conversion factor for the different types of water heaters 
covered within the scope of this rulemaking (as discussed in section 
III.B). This section describes the methodology that was applied to 
develop a conversion factor for each type of water heater.
    In response to the April 2015 NOPR, Rheem commented generally that 
DOE did not specify how it determined whether the proposed UEF 
conversion factors and minimum standards were acceptable and do not 
effectively amend the energy conservation standards. (Rheem, No. 11 at 
p. 5) AHRI stated that the tested UEF values do not align with the 
converted UEF values. (AHRI, No. 13 at p. 4) Regarding the conversion 
factors, DOE examined multiple

[[Page 59761]]

approaches and, in most cases, chose the approach that yielded the 
lowest RMSD value. For certain conversions, DOE chose an approach where 
the RMSD value was slightly higher, but negligibly so, in favor of a 
simpler approach to the conversion. (As stated in section III.E.1, DOE 
tentatively considers a change in RMSD to be negligible if it is less 
than one unit (0.01 for EF and UEF, 0.1 for maximum GPM, and 1.0 for 
first-hour rating).) In examining whether the proposed conversion 
factors are appropriate, DOE considered its certification policies for 
water heaters contained in 10 CFR part 429. Recognizing the variation 
in materials, the manufacturing process, and testing, DOE provides 
bounds on acceptable representations of efficiency for certifying 
represented values. DOE requires the manufacturer to rate the 
efficiency of a basic model between the Federal energy conservation 
standard and up to the lower of the mean of the sample or the 95-
percent lower confidence limit divided by 0.9. 10 CFR 429.17. DOE 
examined the variability between the tested EF and the rated EF for 
each model tested for this rulemaking by determining the standard 
deviation for each sample grouping (i.e., the sample data points 
included for each conversion equation) in order to estimate the amount 
of variation allowed by DOE's rating requirements at 10 CFR 429.17. DOE 
then compared the standard deviation of the tested EF values to the 
RMSD of predicted UEF values.\10\ For all product classes, the RMSD of 
the UEF values was less than or equal to the standard deviation of the 
EF values when rounded to the nearest 0.01, indicating that the 
variability of the predicted conversion values is less than or equal to 
that of the tested EF values observed in a sample of models under the 
current test procedure. In addition, DOE's approach to ensuring the 
energy conservation standards are not effectively amended is discussed 
further in section III.E.3.
---------------------------------------------------------------------------

    \10\ DOE examined RMSD as the measure of the variability between 
tested and predicted UEF values, as it is a common measure of the 
accuracy of a model and is often used to compare predicted and 
measured values. In comparing measured versus rated values for EF, 
DOE examined standard deviation, which represents the variability of 
a sample in relation to the mean of that sample. In this case, DOE 
assumes that the rated EF will represent the mean of the sample. DOE 
recognizes that under its certification regulation, rated EF may 
actually be different from the mean of a sample. For purposes of 
assessing the scope of variability, that difference will not be 
important.
---------------------------------------------------------------------------

    NEEA stated that the April 2015 NOPR did not deliver a set of 
mathematical conversion factors that would enable the marketplace (or 
anyone else) to rely on the resulting UEF ratings or the proposed UEF 
standards equations that are derived from those ratings. (NEEA, No. 15 
at p. 2) DOE disagrees with NEEA, and believes that the UEF values 
predicted using the mathematical conversions are reasonable, as 
evidenced by the resulting RMSD values. RMSD is a measure of the 
differences between values predicted by a model and those actually 
observed. As discussed above, the RMSD values for the predicted UEF 
were less than or equal to the standard deviation of the tested EF 
values for each class of water heater, suggesting that the mathematical 
conversion factors presented are reasonably accurate.
a. Consumer Storage Water Heaters
i. Test Results
    In total, DOE has conducted testing of 55 consumer storage water 
heater models using both the EF and UEF test procedures, and likewise, 
AHRI has supplied test data for 130 consumer storage water heater 
models using both the EF and UEF test procedures.11 12 Table 
III.26 presents the test data used to derive the consumer storage water 
heater conversion factors. Table III.27 shows the water heater 
attributes by unit. DOE notes that 1 of the 2 oil-fired storage water 
heaters, 1 of the 46 electric storage water heaters, and 3 of the 118 
gas-fired storage water heaters that were included in the testing and 
analysis had manufacturer self-declared ratings below the current 
energy conservation standards (compliance required April 16, 2015). 
Although the rated efficiency of these water heaters are below the 
energy conservation standards, DOE believes it is appropriate to use 
data from these models, because the difference between the relevant 
parameters under the new and old test procedures (i.e., first-hour 
rating, EF, and UEF) are likely to be similar to those of a model rated 
to meet the energy conservation standards. Thus, DOE believes this 
model is relevant for evaluating the conversion factor which is 
intended to establish the relationship between ratings under the UEF 
and EF test procedures. Therefore, DOE has considered these models in 
its analysis for determining the mathematical conversion factors.
---------------------------------------------------------------------------

    \11\ The AHRI submitted data points 2-5 and 2-6 were not used in 
this analysis as the reported recovery efficiencies were 98 percent 
and not calculated from test data.
    \12\ If multiple tests were conducted on either the same unit or 
same basic model of a water heater, the results were averaged to 
produce the values reported in this SNOPR. In one instance within 
the AHRI-submitted data for consumer storage water heaters, three 
tests were conducted, where two tests were conducted on the same 
unit and another test was conducted on a unit of the same basic 
model. The two tests of the same unit were averaged, and this value 
was then averaged with the results of the test of the unit of the 
same basic model.

                                                  Table III.26--Consumer Storage Water Heater Test Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Prior
                                                                            Storage     Input    Prior FHR   Updated     recovery
             CS No.                     AHRI No.              Type           volume   rate (Btu/   (gal)       FHR      efficiency      EF        UEF
                                                                             (gal)        h)                  (gal)        (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................  N/A................  Gas...............       36.8     40,000       73.8      104.2         92.2      0.790      0.802
2...............................  N/A................  Gas...............       45.6     39,800       91.0       85.0         96.2      0.836      0.826
3...............................  N/A................  Gas...............       37.8     39,400       74.5       80.9         80.5      0.692      0.714
4...............................  N/A................  Gas...............       49.4     44,100       97.5       86.7         78.8      0.610      0.634
5...............................  N/A................  Gas...............       38.2     38,300       71.4       64.8         76.4      0.625      0.600
6...............................  N/A................  Gas...............       38.0     40,500       73.5       75.7         83.6      0.702      0.719
7...............................  N/A................  Gas...............       37.9     40,100       80.2       63.8         83.6      0.711      0.669
8...............................  N/A................  Gas...............       47.2     50,600       95.2       87.7         78.3      0.608      0.635
9...............................  N/A................  Gas...............       38.1     39,300       71.9       77.8         75.8      0.607      0.635
10..............................  N/A................  Gas...............       27.8     31,600       59.0       64.4         78.8      0.619      0.605
11..............................  N/A................  Gas...............       38.1     40,200       74.9       70.9         78.5      0.618      0.570
12..............................  N/A................  Gas...............       38.8     32,400       68.7       65.1         77.9      0.664      0.624
13..............................  N/A................  Gas...............       38.4     39,800       70.2       74.1         80.4      0.673      0.654
14..............................  N/A................  Gas...............       27.7     59,600       96.9       94.6         78.2      0.702      0.718

[[Page 59762]]

 
15..............................  N/A................  Gas...............       38.4     36,300       66.0       68.1         85.0      0.699      0.677
16..............................  N/A................  Gas...............       47.9     49,900       90.2       81.1         81.1      0.674      0.676
17..............................  N/A................  Gas...............       47.8     64,600      108.0      108.8         79.8      0.654      0.680
18..............................  N/A................  Gas...............       38.4     40,000       67.0       81.1         80.5      0.601      0.628
19..............................  N/A................  Gas...............       37.8     39,700       70.2       87.0         80.2      0.610      0.641
20..............................  N/A................  Gas...............       38.1     40,300       68.3       64.8         74.1      0.602      0.598
21..............................  N/A................  Gas...............       28.6     33,000       56.1       70.6         82.2      0.610      0.561
22..............................  N/A................  Gas...............       48.1     36,000       92.1       88.2         80.6      0.630      0.662
23..............................  N/A................  Gas...............       47.7     40,500       94.2       84.0         72.5      0.547      0.640
24..............................  N/A................  Gas...............       26.5     29,500       50.4       51.5         80.8      0.644      0.603
25..............................  N/A................  Gas...............       45.6     39,700       87.9       83.2         77.8      0.593      0.617
26..............................  N/A................  Gas...............       54.1     44,800      103.2       97.9         77.2      0.577      0.596
27..............................  N/A................  Oil...............       30.1    104,000      112.5      127.4         89.4      0.605      0.641
28..............................  N/A................  Oil...............       29.8    105,100      104.8      111.6         71.4      0.518      0.528
29..............................  N/A................  Electric..........       25.7     15,100       41.4       39.7         98.0      0.949      0.903
30..............................  N/A................  Electric..........       25.8     15,400       42.9       42.9         98.0      0.936      0.891
31..............................  N/A................  Electric..........       35.0     15,400       55.5       52.3         98.0      0.941      0.937
32..............................  N/A................  Electric..........       25.1     16,300       40.8       46.2         98.0      0.944      0.902
33..............................  N/A................  Electric..........       36.2     15,200       53.2       50.0         98.0      0.940      0.906
34..............................  N/A................  Electric..........       45.1     15,300       56.5       65.3         98.0      0.930      0.909
35..............................  N/A................  Electric..........       46.0     14,800       66.8       59.9         98.0      0.917      0.932
36..............................  N/A................  Electric..........       46.0     15,400       61.1       59.8         98.0      0.948      0.946
37..............................  N/A................  Electric..........       26.7     13,000       38.7       43.2         98.0      0.912      0.902
38..............................  N/A................  Electric..........       49.7     18,100       68.6       73.3         98.0      0.914      0.942
39..............................  N/A................  Electric..........       35.8     15,000       53.8       48.5         98.0      0.927      0.868
40..............................  N/A................  Electric..........       45.3     15,400       62.7       64.2         98.0      0.922      0.931
41..............................  N/A................  Electric..........       45.2     15,000       66.1       68.7         98.0      0.949      0.919
42..............................  N/A................  Electric..........       36.0     14,900       53.8       54.8         98.0      0.917      0.941
43..............................  N/A................  Electric..........       44.8     14,800       64.9       59.4         98.0      0.958      0.926
44..............................  N/A................  Electric..........       54.5     15,300       80.7       77.2         98.0      0.959      0.952
45..............................  N/A................  Electric..........       45.0     15,200       63.7       56.8         98.0      0.937      0.904
46..............................  N/A................  Electric..........       44.7     15,600       60.7       64.8         98.0      0.915      0.901
47..............................  N/A................  Electric..........       35.9     15,400       52.4       51.9         98.0      0.932      0.922
48..............................  N/A................  Tabletop..........       35.0     15,200       52.9       48.0         98.0      0.877      0.805
49..............................  N/A................  Tabletop..........       25.0     15,400       37.5       45.3         98.0      0.905      0.859
50..............................  N/A................  Heat Pump.........       45.4     15,400       64.5       56.1        282.9      2.486      1.948
51..............................  N/A................  Heat Pump.........       45.5     15,000       57.3       58.9        270.3      2.270      2.572
52..............................  N/A................  Heat Pump.........       45.1     11,100       59.1       48.7        264.7      2.260      2.071
53..............................  N/A................  Heat Pump.........       58.8     15,300       71.5       68.6        296.9      2.280      2.496
54..............................  N/A................  Heat Pump.........       77.5     15,700       90.5       87.1        288.2      2.270      2.642
55..............................  N/A................  Heat Pump.........       80.8      1,800       57.0       58.0        288.0      2.330      2.540
56..............................  1-1................  Gas...............       45.7     39,300       91.6       86.9         91.0      0.789      0.806
57..............................  1-2................  Gas...............       47.9     40,400       89.5       77.3         80.3      0.682      0.704
58..............................  CGS-11.............  Gas...............       47.5     40,600       87.5       78.8         83.5      0.697      0.729
59..............................  1-6................  Gas...............       39.0     39,900       65.2       75.6         77.6      0.600      0.653
60..............................  1-11...............  Gas...............       28.8     29,600       55.4       52.8         80.2      0.636      0.597
61..............................  1-34...............  Gas...............       38.0     39,900       68.5       69.5         82.3      0.649      0.595
62..............................  1-41...............  Gas...............       38.2     38,500       70.0       75.9         85.7      0.719      0.750
63..............................  CGS-14.............  Gas...............       48.5     40,200       94.9       89.5         82.9      0.625      0.649
64..............................  CGS-19.............  Gas...............       27.9     35,400       66.8       67.9         79.9      0.626      0.597
65..............................  CGS-23.............  Gas...............       49.3     39,500       89.2       70.0         77.1      0.587      0.560
66..............................  CGS-26.............  Gas...............       28.7     30,600       52.5       51.9         77.4      0.612      0.578
67..............................  CGS-32.............  Gas...............       38.3     37,400       74.4       70.6         78.7      0.645      0.651
68..............................  CGS-36.............  Gas...............       38.6     34,700       74.9       68.0         79.5      0.624      0.574
69..............................  CGS-37.............  Gas...............       39.0     38,600       71.3       62.5         81.0      0.622      0.577
70..............................  CGS-38.............  Gas...............       28.7     30,600       55.1       59.6         78.8      0.625      0.596
71..............................  CGS-4..............  Gas...............       38.7     40,100       64.2       78.8         79.1      0.602      0.637
72..............................  CGS-6..............  Gas...............       47.4     50,500       84.9      115.0         78.8      0.580      0.611
73..............................  CGS-8..............  Gas...............       48.3     37,600       84.1       78.5         79.5      0.675      0.711
74..............................  1-9................  Gas...............       28.2     59,100       93.0       97.9         80.3      0.688      0.718
75..............................  1-4................  Gas...............       47.9     39,200       88.4       80.7         79.7      0.605      0.656
76..............................  1-7................  Gas...............       47.9     35,300       79.5       69.6         81.8      0.608      0.580
77..............................  1-8................  Gas...............       47.9     40,200       78.0       70.8         79.0      0.596      0.593
78..............................  1-12...............  Gas...............       38.2     37,800       75.0       71.5         79.4      0.632      0.558
79..............................  1-13...............  Gas...............       48.0     37,700       94.7       87.2         77.6      0.597      0.613
80..............................  1-14...............  Gas...............       47.6     37,700       86.3       81.7         75.9      0.575      0.611
81..............................  1-15...............  Gas...............       28.0     31,400       57.1       50.6         83.5      0.648      0.598
82..............................  1-17...............  Gas...............       47.8     37,900       87.4       81.7         80.8      0.592      0.622
83..............................  1-18...............  Gas...............       38.9     37,400       75.4       73.6         81.8      0.633      0.588

[[Page 59763]]

 
84..............................  1-30...............  Gas...............       47.8     40,000       83.0       73.0         79.0      0.610      0.580
85..............................  1-33...............  Gas...............       48.0     40,000       83.5       67.0         79.0      0.610      0.640
86..............................  CGS-1..............  Gas...............       37.8     39,300       67.7       83.8         78.8      0.611      0.654
87..............................  CGS-13.............  Gas...............       47.9     36,300       75.6       84.4         78.3      0.588      0.644
88..............................  CGS-15.............  Gas...............       54.9     49,600      100.1       89.3         83.5      0.618      0.646
89..............................  CGS-17.............  Gas...............       28.8     29,600       51.8       48.2         81.6      0.679      0.603
90..............................  CGS-18.............  Gas...............       38.3     33,400       56.1       50.7         82.6      0.633      0.535
91..............................  CGS-2..............  Gas...............       47.7     40,300       87.2       80.8         77.7      0.605      0.614
92..............................  CGS-21.............  Gas...............       28.7     36,000       67.8       65.1         85.0      0.657      0.620
93..............................  CGS-22.............  Gas...............       47.8     39,600       78.2       71.8         80.7      0.615      0.557
94..............................  CGS-24.............  Gas...............       38.8     34,500       59.9       59.9         77.4      0.606      0.588
95..............................  CGS-25.............  Gas...............       47.6     40,400       84.3       74.6         77.0      0.585      0.556
96..............................  CGS-3..............  Gas...............       47.6     40,800       83.1       75.9         83.0      0.634      0.669
97..............................  CGS-30.............  Gas...............       28.7     32,100       63.0       55.0         79.7      0.623      0.607
98..............................  CGS-33.............  Gas...............       26.6     31,900       52.8       57.8         81.2      0.647      0.623
99..............................  CGS-34.............  Gas...............       28.4     29,900       52.3       60.4         83.7      0.630      0.596
100.............................  CGS-39.............  Gas...............       38.3     35,500       76.7       72.0         79.1      0.613      0.552
101.............................  CGS-40.............  Gas...............       38.4     29,400       59.0       53.7         77.3      0.596      0.556
102.............................  CGS-41.............  Gas...............       38.3     37,400       73.7       68.6         81.4      0.634      0.620
103.............................  CGS-5..............  Gas...............       48.5     40,100       89.2       82.3         80.5      0.619      0.652
104.............................  CGS-7..............  Gas...............       46.1     64,500      103.3      130.2         83.9      0.601      0.646
105.............................  2-1................  Gas...............       28.6     32,000       81.1       67.7         82.5      0.653      0.621
106.............................  2-3................  Gas...............       45.7     64,900      100.0      113.0         82.5      0.624      0.654
107.............................  1-5, 10............  Gas...............       38.4     39,500       65.7       64.9         79.1      0.602      0.571
108.............................  1-35...............  Gas...............       46.0     60,000      100.0      113.0         82.5      0.624      0.654
109.............................  1-36...............  Gas...............       38.1     39,300       71.8       68.6         81.2      0.688      0.633
110.............................  1-43...............  Gas...............       38.1     39,300       69.3       68.6         79.8      0.675      0.646
111.............................  CGS-12.............  Gas...............       49.7     39,400       90.6       81.5         81.6      0.699      0.713
112.............................  CGS-31.............  Gas...............       38.3     39,700       70.8       66.0         78.0      0.651      0.626
113.............................  CGS-35.............  Gas...............       38.2     40,600       69.4       67.3         80.5      0.691      0.662
114.............................  2-2................  Gas...............       48.2     39,800       83.6       81.3         77.5      0.652      0.689
115.............................  1-3................  Gas...............       48.1     41,200       87.9       80.1         75.2      0.640      0.685
116.............................  1-37...............  Gas...............       48.1     39,400       86.5       82.9         80.0      0.666      0.646
117.............................  CGS-10.............  Gas...............       38.1     37,800       71.7       78.5         82.9      0.697      0.725
118.............................  CGS-16.............  Gas...............       47.9     65,700      112.5      114.4         78.3      0.642      0.693
119.............................  CGS-9..............  Gas...............       48.6     39,800       92.5       90.7         81.6      0.689      0.704
120.............................  1-22...............  Gas...............       39.1     40,100       69.4       87.9         79.3      0.667      0.699
121.............................  1-51...............  Gas...............       38.4     38,100       71.2       65.1         79.5      0.614      0.576
122.............................  1-19...............  Gas...............       38.2     40,700       77.2       65.8         80.0      0.680      0.658
123.............................  1-21...............  Gas...............       48.1     40,400       87.5       82.0         76.6      0.606      0.639
124.............................  1-25...............  Gas...............       48.2     39,500       86.6       76.5         79.2      0.590      0.636
125.............................  1-50...............  Gas...............       48.1     39,700       91.7       78.6         80.9      0.612      0.636
126.............................  1-47...............  Gas...............       38.1     39,600       68.6       77.4         79.7      0.679      0.689
127.............................  1-48...............  Gas...............       47.5     61,400      112.0      104.9         82.1      0.683      0.690
128.............................  1-49...............  Gas...............       47.5     39,500       85.2       75.9         81.3      0.661      0.674
129.............................  1-20...............  Gas...............       47.9     49,700       92.4       86.5         81.7      0.673      0.676
130.............................  1-52...............  Gas...............       47.9     44,100       86.9       79.7         81.2      0.682      0.691
131.............................  1-16...............  Gas...............       36.8     36,000       67.3       61.6         80.9      0.615      0.592
132.............................  1-44...............  Gas...............       48.6     39,200       94.8       91.6         77.4      0.625      0.613
133.............................  1-27, 28, 29.......  Gas...............       39.0     35,900       62.6       61.1         79.4      0.625      0.602
134.............................  1-26...............  Gas...............       48.1     38,200       83.5       73.9         82.7      0.634      0.592
135.............................  1-45...............  Gas...............       38.0     39,300       74.4       75.1         78.3      0.623      0.647
136.............................  CGS-20.............  Gas...............       37.8     39,900       75.0       68.4         78.0      0.575      0.529
137.............................  CGS-27.............  Gas...............       28.9     30,500       57.0       67.7         79.3      0.628      0.597
138.............................  CGS-28.............  Gas...............       38.3     40,700       72.9       66.9         79.3      0.578      0.529
139.............................  CGS-29.............  Gas...............       39.4     40,800       72.0       73.5         78.3      0.602      0.580
140.............................  1-40...............  Gas...............       38.1     40,700       71.8       68.8         77.1      0.610      0.648
141.............................  1-42...............  Gas...............       48.3     39,800       86.0       85.8         80.9      0.673      0.715
142.............................  1-46...............  Gas...............       38.3     39,200       71.8       68.1         79.1      0.660      0.633
143.............................  1-23...............  Gas...............       38.3     41,600       68.2       84.7         82.6      0.677      0.699
144.............................  1-31...............  Gas...............       47.9     42,000       68.0       85.0         82.0      0.680      0.700
145.............................  1-38...............  Gas...............       37.8     39,200       87.2       66.5         80.2      0.682      0.560
146.............................  1-39...............  Gas...............       46.1     50,000       97.4       92.6         81.8      0.669      0.688
147.............................  1-24, 32...........  Gas...............       48.1     42,100       80.2       74.0         87.2      0.710      0.682
148.............................  1-68...............  Electric..........       36.1     15,400       53.6       51.2         98.0      0.961      0.942
149.............................  CES-11.............  Electric..........       28.6     15,400       42.1       45.9         98.0      0.947      0.897
150.............................  CES-12.............  Electric..........       38.4     15,400       49.7       57.4         98.0      0.944      0.922
151.............................  CES-13.............  Electric..........       49.8     15,400       63.6       63.3         98.0      0.954      0.911
152.............................  CES-14.............  Electric..........       48.6     15,400       59.4       54.3         98.0      0.923      0.920

[[Page 59764]]

 
153.............................  CES-2..............  Electric..........       25.8     15,400       41.1       38.6         98.0      0.937      0.897
154.............................  CES-3..............  Electric..........       25.6     15,400       43.7       41.4         98.0      0.911      0.890
155.............................  CES-4..............  Electric..........       34.7     15,400       52.5       57.3         98.0      0.935      0.938
156.............................  CES-5..............  Electric..........       27.7     15,400       46.4       49.1         98.0      0.940      0.898
157.............................  CES-6..............  Electric..........       54.7     15,400       80.5       66.4         98.0      0.933      0.933
158.............................  CES-7..............  Electric..........       45.2     15,400       66.4       64.2         98.0      0.939      0.912
159.............................  CES-8..............  Electric..........       45.2     15,400       63.7       60.7         98.0      0.930      0.910
160.............................  CES-9..............  Electric..........       36.1     15,400       54.2       51.5         98.0      0.914      0.888
161.............................  2-4................  Electric..........       39.0     15,400       59.0       55.0         98.0      0.950      0.920
162.............................  2-7................  Electric..........       40.6     15,400       64.9       59.4         98.0      0.960      0.926
163.............................  2-8................  Electric..........       27.3     15,400       45.3       36.5         98.0      0.962      0.878
164.............................  1-64...............  Electric..........       36.3     15,400       55.0       52.0         98.0      0.950      0.950
165.............................  1-65...............  Electric..........       45.7     15,400       58.0       61.0         98.0      0.940      0.930
166.............................  1-66...............  Electric..........       27.1     15,400       48.0       48.0         98.0      0.930      0.870
167.............................  1-53...............  Electric..........       45.5     15,400       64.3       60.1         98.0      0.939      0.919
168.............................  1-54...............  Electric..........       36.4     15,400       53.9       55.6         98.0      0.932      0.929
169.............................  1-56...............  Electric..........       27.4     15,400       47.7       42.1         98.0      0.943      0.911
170.............................  1-57...............  Electric..........       36.4     15,400       57.5       51.3         98.0      0.941      0.915
171.............................  1-58...............  Electric..........       54.8     15,400       71.0       61.1         98.0      0.936      0.907
172.............................  1-59...............  Electric..........       36.2     15,400       59.1       57.0         98.0      0.941      0.931
173.............................  1-69...............  Electric..........       45.4     15,400       59.3       58.3         98.0      0.947      0.922
174.............................  1-60, 61, 62.......  Electric..........       48.0     15,400       65.3       61.0         98.0      0.940      0.910
175.............................  1-55...............  Tabletop..........       36.0     15,400       45.6       58.3         98.0      0.873      0.873
176.............................  1-70...............  Heat Pump.........       45.4     15,700       64.5       61.1        289.0      2.450      2.470
177.............................  CES-1..............  Heat Pump.........       81.8     15,400       98.4       94.6        304.8      2.617      2.439
178.............................  CES-10.............  Heat Pump.........       45.6     15,700       69.3       64.1        369.5      3.278      3.270
179.............................  CES-15.............  Heat Pump.........       73.3     16,000       74.9       78.4        249.3      2.297      2.424
180.............................  CES-16.............  Heat Pump.........      107.9     16,000      101.7      100.1        214.0      1.971      2.137
181.............................  CES-17.............  Heat Pump.........       58.7     16,000       71.3       52.3        246.4      2.291      2.219
182.............................  1-71, 72...........  Heat Pump.........       45.5     15,700       69.2       66.1        366.7      3.230      3.140
183.............................  1-76...............  Heat Pump.........       75.5     15,700       96.0       89.6        386.5      3.310      3.330
184.............................  1-63, 67...........  Heat Pump.........       77.5     15,400       81.8       74.8        262.1      2.242      2.270
185.............................  1-73, 74, 75.......  Heat Pump.........       75.5     15,700       95.7       89.4        368.1      3.207      3.186
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                                 Table III.27--Consumer Storage Water Heater Attributes
--------------------------------------------------------------------------------------------------------------------------------------------------------
               CS No.                  NOX Emission level          Condensing              Vent type            Short or tall          Standing pilot
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................  Low...................  Yes...................  Power................  Short................  No.
2..................................  Low...................  Yes...................  Power................  Tall.................  No.
3..................................  Low...................  No....................  Atmospheric..........  Short................  No.
4..................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
5..................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
6..................................  Low...................  No....................  Atmospheric..........  Tall.................  No.
7..................................  Low...................  No....................  Atmospheric..........  Tall.................  No.
8..................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
9..................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
10.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
11.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
12.................................  Low...................  No....................  Power................  Short................  No.
13.................................  Low...................  No....................  Power................  Short................  No.
14.................................  Low...................  No....................  Power................  Tall.................  No.
15.................................  Low...................  No....................  Power................  Tall.................  No.
16.................................  Low...................  No....................  Power................  Tall.................  No.
17.................................  Low...................  No....................  Power................  Tall.................  No.
18.................................  Standard..............  No....................  Atmospheric..........  Short................  Yes.
19.................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
20.................................  Ultra-Low.............  No....................  Atmospheric..........  Short................  Yes.
21.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
22.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
23.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
24.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
25.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
26.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
27.................................  N/A...................  N/A...................  N/A..................  Tall.................  No.
28.................................  N/A...................  N/A...................  N/A..................  Tall.................  No.
29.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
30.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.

[[Page 59765]]

 
31.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
32.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
33.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
34.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
35.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
36.................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
37.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
38.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
39.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
40.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
41.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
42.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
43.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
44.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
45.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
46.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
47.................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
48.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
49.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
50.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
51.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
52.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
53.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
54.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
55.................................  N/A...................  N/A...................  N/A..................  N/A..................  N/A.
56.................................  Low...................  Yes...................  Power................  Tall.................  No.
57.................................  Low...................  No....................  Atmospheric..........  Short................  No.
58.................................  Low...................  No....................  Atmospheric..........  Short................  No.
59.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
60.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
61.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
62.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
63.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
64.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
65.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
66.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
67.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
68.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
69.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
70.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
71.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
72.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
73.................................  Low...................  No....................  Atmospheric..........  Short................  Yes.
74.................................  Low...................  No....................  Atmospheric..........  Tall.................  No.
75.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
76.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
77.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
78.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
79.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
80.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
81.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
82.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
83.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
84.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
85.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
86.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
87.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
88.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
89.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
90.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
91.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
92.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
93.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
94.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
95.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
96.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
97.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
98.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
99.................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
100................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
101................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
102................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.

[[Page 59766]]

 
103................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
104................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
105................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
106................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
107................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
108................................  Low...................  No....................  Not Specified........  Not Specified........  Not Specified.
109................................  Low...................  No....................  Power................  Short................  No.
110................................  Low...................  No....................  Power................  Short................  No.
111................................  Low...................  No....................  Power................  Short................  No.
112................................  Low...................  No....................  Power................  Short................  No.
113................................  Low...................  No....................  Power................  Short................  No.
114................................  Low...................  No....................  Power................  Short................  No.
115................................  Low...................  No....................  Power................  Tall.................  No.
116................................  Low...................  No....................  Power................  Tall.................  No.
117................................  Low...................  No....................  Power................  Tall.................  No.
118................................  Low...................  No....................  Power................  Tall.................  No.
119................................  Low...................  No....................  Power................  Tall.................  No.
120................................  Standard..............  No....................  Atmospheric..........  Short................  No.
121................................  Standard..............  No....................  Atmospheric..........  Short................  Yes.
122................................  Standard..............  No....................  Atmospheric..........  Tall.................  No.
123................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
124................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
125................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
126................................  Standard..............  No....................  Power................  Short................  No.
127................................  Standard..............  No....................  Power................  Short................  No.
128................................  Standard..............  No....................  Power................  Short................  No.
129................................  Standard..............  No....................  Power................  Tall.................  No.
130................................  Standard..............  No....................  Power................  Tall.................  No.
131................................  Ultra-Low.............  No....................  Atmospheric..........  Short................  Yes.
132................................  Ultra-Low.............  No....................  Atmospheric..........  Short................  Yes.
133................................  Ultra-Low.............  No....................  Atmospheric..........  Short................  Yes.
134................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
135................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
136................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
137................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
138................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
139................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
140................................  Ultra-Low.............  No....................  Power................  Short................  No.
141................................  Ultra-Low.............  No....................  Power................  Short................  No.
142................................  Ultra-Low.............  No....................  Power................  Short................  No.
143................................  Ultra-Low.............  No....................  Power................  Tall.................  No.
144................................  Ultra-Low.............  No....................  Power................  Tall.................  No.
145................................  Ultra-Low.............  No....................  Power................  Tall.................  No.
146................................  Ultra-Low.............  No....................  Power................  Tall.................  No.
147................................  Ultra-Low.............  No....................  Power................  Tall.................  No.
148................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
149................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
150................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
151................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
152................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
153................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
154................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
155................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
156................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
157................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
158................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
159................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
160................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
161................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
162................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
163................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
164................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
165................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
166................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
167................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
168................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
169................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
170................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
171................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
172................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
173................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
174................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.

[[Page 59767]]

 
175................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
176................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
177................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
178................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
179................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
180................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
181................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
182................................  N/A...................  N/A...................  N/A..................  Not Specified........  N/A.
183................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
184................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A.
185................................  N/A...................  N/A...................  N/A..................  Tall.................  N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------

ii. Conversion Factor Results
    For consumer storage water heaters, DOE is proposing to use the 
regression method described in section III.C.5 to predict first-hour 
ratings (FHRs) under the UEF test procedure to be used in the 
conversion to UEF since no ``analytical approach'' has been developed. 
Of the factors considered, DOE found that the first-hour rating 
determined under the EF test procedure was the best overall predictor 
of the new first-hour rating. These findings were based on the RMSDs 
between predictions and measured values. The resulting equations, which 
are proposed for determining the new FHR of consumer storage water 
heaters, are presented in Table III.28.

 Table III.28--Proposed Consumer Storage Water Heater First-Hour Rating
                       Conversion Factor Equations
------------------------------------------------------------------------
                                    Distinguishing
          Product class                criteria        Conversion factor
------------------------------------------------------------------------
Consumer Gas-fired Water Heater.  Non-Condensing,     New FHR = 7.9592 +
                                   Standard or Low     0.8752 x FHRP.
                                   NOX.               New FHR = 25.0680
                                  Non-Condensing,      + 0.6535 x FHRP.
                                   Ultra-Low NOX.     New FHR = 1.0570 x
                                  Condensing........   FHRP.
Consumer Oil-fired Water Heater.  N/A...............  New FHR = 1.1012 x
                                                       FHRP.
Consumer Electric Water Heater..  Electric            New FHR = 9.2827 +
                                   Resistance.         0.8092 x FHRP.
                                  Tabletop..........  New FHR = 41.5127
                                  Heat Pump.........   + 0.1989 x FHRP.
                                                      New FHR = -4.2705
                                                       + 0.9947 x FHRP.
------------------------------------------------------------------------

    New FHR is the predicted first-hour rating that would result under 
the UEF test method and is used for conversion to UEF; FHRP 
is the first-hour rating determined under the EF test procedure, and 
the slope and intercept are constants obtained from a linear 
regression. While most of the data allowed for such a regression fit, 
in two cases (condensing gas-fired and oil-fired) the available data 
were too limited to produce reliable regressions for the full set of 
parameters. To constrain the regression so as to generate more reliable 
predictions for those smaller sets of data, the intercepts of the 
regressions were assigned a value of zero, meaning that a water heater 
with an FHRP of zero would also have a New FHR of zero. This 
assignment is reasonable because if a hypothetical water heater were 
not able to deliver any water under the EF test procedure, it also 
would not be able to deliver water under the UEF test procedure.
    In response to the first-hour rating mathematical conversion 
developed in the NOPR, AHRI argued that the results are often 
inconsistent and show no trend, particularly for the consumer gas-fired 
storage product class in the medium and high draw patterns. (AHRI, No. 
13 at p. 2) Bradford White commented that its testing showed that the 
FHR for most models went down with the change in test procedure, some 
of which were affected more than others. (Bradford White, No. 14 at p. 
2) NEEA stated that the conversion factors that convert prior FHR 
ratings to new FHR ratings produce unacceptably large deviations from 
the measured FHR ratings for a significant majority of the water 
heaters tested. Further, NEEA commented that these large variations 
caused 9 of 43 water heaters tested to fall into a different draw bin 
using the conversion as compared to the tested rating, and it 
recommended that given the critical nature of the FHR in selecting the 
proper draw pattern, DOE should not attempt to mathematically derive 
FHR and maximum GPM ratings, but should instead require them to be 
measured in accordance with the new test procedures. (NEEA, No. 15 at 
pp. 5-6)
    In response, DOE notes that it explored several possible 
conversions for developing the FHR conversion. The best trend was 
observed based on a regression as a function of first-hour rating. The 
average RMSD value resulting from this approach (7.56 gallons) is the 
lowest RMSD observed in the FHR analysis, and DOE is unaware of any 
approaches that would result in improved accuracy. Further, as 
discussed above in section III.E.2, the predicted UEF values (which are 
based in part on the predicted FHR values due to the dependence of draw 
pattern on FHR) are reasonable because they are less than the 
variability currently allowed in DOE's regulations that manufacturers 
are required to use and rate their basic models. DOE seeks further 
comment regarding other methods for predicting FHR that could result in 
lower RMSDs. In the absence of any known alternatives, DOE plans to 
continue the use of this methodology, but seeks further comment on 
other approaches for converting first-hour ratings.
    After determining the converted first-hour rating, the next step in 
the conversion process is to determine which draw pattern is to be 
applied to convert from EF to UEF. After the first-hour rating under 
the uniform efficiency descriptor is determined using the conversion 
factor above, the value can be applied to determine the appropriate 
draw pattern bin (i.e., very small, low, medium, or high) using Table 1 
of the

[[Page 59768]]

uniform efficiency descriptor test procedure. 10 CFR 430, Subpart B, 
Appendix E, section 5.4.1. With the draw bin known, the UEF value based 
on the WHAM analytical model can be calculated using the process 
described in section III.C.4.c for all consumer water heater types. 
Alternatively, DOE investigated the step regression approach described 
in section III.C.2 to convert EF to UEF. As described in the April 2015 
NOPR, DOE found that a third technique, a combination of these 
approaches in which the results of the WHAM analytical model are used 
as the independent variable in a standard linear regression analysis, 
produced a conversion with the lowest RMSD observed. 80 FR 20116, 20132 
(April 14, 2015). Separate conversion equations were developed for the 
same categories as used for first-hour rating. The results of the 
first-hour regression, the WHAM analytical model, the step regression 
model, and the combined WHAM-regression model are presented in Table 
III.30. In light of the additional data compiled for the SNOPR, the 
RMSD for the non-heat pump storage water heater classes is 0.018 when 
using a combined WHAM-regression model, and as noted, this is the 
lowest RMSD observed. DOE, therefore, continues to propose the use of 
the combined WHAM-regression approach to calculate the conversion 
factor for all types of consumer storage water heaters except for heat 
pump water heaters. The WHAM-regression approach accounts for the test 
procedure changes in terms of daily volume delivered and storage tank 
temperature, and it corrects for the unaccounted changes using a 
regression with actual test data. The resulting equations for 
determining the UEF of consumer storage water heaters are shown in 
Table III.29.
    For heat pump water heaters, DOE determined in the April 2015 NOPR 
that, although the relevant data can be obtained through testing (and 
for the units tested by DOE were obtained), the data are not available 
within the certification databases to compute the WHAM estimate for 
heat pump water heaters on the market; therefore, a linear regression 
equation was developed in which the UEF is estimated solely based on 
the EF. 80 FR 20116, 20132 (April 14, 2015). DOE received no comments 
submitting data on this point or identifying sources from which DOE 
could obtain such data. In this SNOPR, DOE proposes that manufacturers 
should apply the conversions to their test data directly, and then the 
converted test values will be used to rate the water heater model in 
accordance with the certification provisions found in 10 CFR 429.17. 
Because both DOE's data from its testing and the test data submitted by 
AHRI include all of the necessary information to estimate the 
efficiency using the WHAM equation, WHAM and WHAM-Regression 
conversions can be derived based on the tested values. Under either of 
these approaches, manufacturers would use data from EF tests that is 
generally not publicly-available (e.g., the recovery efficiency of the 
heat pump) along with a WHAM-based equation to convert to the UEF 
metric. The WHAM, regression (modified from the NOPR proposal as 
discussed immediately below), and WHAM-Regression conversion approaches 
result in RMSD values of 0.219, 0.194, and 0.197, respectively. The 
regression approach was modified as discussed below and has the lowest 
RMSD value, and, therefore, DOE continues to propose to use the 
regression conversion approach for converting to UEF for HPWH.
    GE stated that the proposed conversion for HPWH is inaccurate, and 
suggested including drawn volume as an independent variable in the 
regression analysis to improve the conversion for high-EF heat pump 
water heaters. (GE, No. 12 at p. 1) GE also provided an equation which 
related EF and drawn volume to UEF. (GE, No. 12 at p. 4) DOE considered 
these suggestions and agrees that the inclusion of drawn volume as a 
regression variable would help improve the conversion factor, so DOE 
has updated the equation appropriately. The GE equation and the new 
DOE-derived conversion factor results in RMSD values of 0.229 and 
0.194, respectively, which is an improvement over the previous 
conversion factor's RMSD value for heat pump water heaters, which is 
0.438 (recalculated with new test data). 80 FR 20116, 20133 (April 14, 
2015). Even after considering the large disparity between EF standards 
and the rated EF values for heat pump water heaters, DOE has 
nonetheless tentatively concluded that this relatively high RMSD would 
not cause a water heater to fail to meet the standards based on UEF. 
Furthermore, the disparity between the UEF of heat pump water heaters 
and electric resistance water heaters is large enough that consumers 
would still be made aware of the significant increase in efficiency 
that heat pump water heaters provide over electric resistance water 
heaters.
    In the equations in Table III.29, UEFWHAM is the 
conversion factor calculated using the WHAM analytical model, described 
in section III.C.4.c, EF is the measured energy factor, and DV is the 
drawn volume in gallons.

 Table III.29--Proposed Consumer Storage UEF Conversion Factor Equations
------------------------------------------------------------------------
                                    Distinguishing     Conversion factor
          Product class                criteria                *
------------------------------------------------------------------------
Consumer Gas-fired Water Heater.  Non-Condensing,     New UEF = -0.0002
                                   Standard or Low     + 0.9858 x
                                   NOX.                UEFWHAM.
                                  Non-Condensing,     New UEF = 0.0746 +
                                   Ultra-Low NOX.      0.8653 x UEFWHAM.
                                  Condensing........  New UEF = 0.4242 +
                                                       0.4641 x UEFWHAM.
Consumer Oil-fired Water Heater.  N/A...............  New UEF = -0.0934
                                                       + 1.1144 x
                                                       UEFWHAM.
Consumer Electric Water Heater..  Conventional......  New UEF = 0.4774 +
                                  Tabletop..........   0.4740 x UEFWHAM.
                                  Heat Pump.........  New UEF = -0.3305
                                                       + 1.3983 x
                                                       UEFWHAM.
                                                      New UEF = 0.1513 +
                                                       0.8407 x EF +
                                                       0.0043 x DV.
------------------------------------------------------------------------


                      Table III.30--Consumer Storage Water Heater Conversion Factor Results
----------------------------------------------------------------------------------------------------------------
                                                                                                        WHAM-
              CS No.                 Tested FHR   Regression   Tested UEF    WHAM UEF    Regression   Regression
                                       (gal)      FHR  (gal)                                UEF          UEF
----------------------------------------------------------------------------------------------------------------
1.................................        104.2         78.0        0.802        0.821        0.805        0.805
2.................................         85.0         96.2        0.826        0.865        0.826        0.826
3.................................         80.9         73.2        0.714        0.718        0.685        0.708
4.................................         86.7         93.3        0.634        0.648        0.611        0.638

[[Page 59769]]

 
5.................................         64.8         70.4        0.600        0.607        0.624        0.599
6.................................         75.7         72.3        0.719        0.732        0.694        0.722
7.................................         63.8         78.1        0.669        0.694        0.702        0.684
8.................................         87.7         91.3        0.635        0.645        0.608        0.635
9.................................         77.8         70.9        0.635        0.640        0.608        0.631
10................................         64.4         59.6        0.605        0.598        0.618        0.589
11................................         70.9         73.5        0.570        0.598        0.618        0.590
12................................         65.1         68.1        0.624        0.649        0.660        0.639
13................................         74.1         69.4        0.654        0.656        0.668        0.647
14................................         94.6         92.8        0.718        0.721        0.695        0.711
15................................         68.1         65.7        0.677        0.679        0.691        0.670
16................................         81.1         86.9        0.676        0.705        0.669        0.694
17................................        108.8        102.5        0.680        0.686        0.651        0.676
18................................         81.1         66.6        0.628        0.643        0.602        0.634
19................................         87.0         69.4        0.641        0.650        0.611        0.641
20................................         64.8         69.7        0.598        0.584        0.600        0.580
21................................         70.6         61.7        0.561        0.586        0.607        0.582
22................................         88.2         85.2        0.662        0.668        0.622        0.652
23................................         84.0         86.6        0.640        0.584        0.559        0.580
24................................         51.5         58.0        0.603        0.623        0.632        0.613
25................................         83.2         82.5        0.617        0.632        0.594        0.622
26................................         97.9         92.5        0.596        0.617        0.582        0.609
27................................        127.4        123.8        0.641        0.659        0.641        0.641
28................................        111.6        115.4        0.528        0.557        0.528        0.528
29................................         39.7         42.8        0.903        0.926        0.922        0.916
30................................         42.9         44.0        0.891        0.905        0.912        0.906
31................................         52.3         54.2        0.937        0.935        0.917        0.921
32................................         46.2         42.3        0.902        0.919        0.919        0.913
33................................         50.0         52.3        0.906        0.912        0.916        0.910
34................................         65.3         55.0        0.909        0.922        0.908        0.914
35................................         59.9         63.3        0.932        0.906        0.898        0.907
36................................         59.8         58.7        0.946        0.943        0.922        0.924
37................................         43.2         40.6        0.902        0.866        0.894        0.888
38................................         73.3         64.8        0.942        0.903        0.895        0.906
39................................         48.5         52.8        0.868        0.891        0.906        0.900
40................................         64.2         60.0        0.931        0.912        0.902        0.910
41................................         68.7         62.8        0.919        0.944        0.923        0.925
42................................         54.8         52.8        0.941        0.906        0.898        0.907
43................................         59.4         61.8        0.926        0.955        0.930        0.930
44................................         77.2         74.6        0.952        0.965        0.930        0.935
45................................         56.8         60.9        0.904        0.930        0.913        0.918
46................................         64.8         58.4        0.901        0.905        0.897        0.906
47................................         51.9         51.7        0.922        0.923        0.909        0.915
48................................         48.0         52.0        0.805        0.812        0.867        0.805
49................................         45.3         49.0        0.859        0.855        0.888        0.865
50................................         56.1         59.9        1.948        2.441        2.478        2.494
51................................         58.9         52.7        2.572        2.215        2.296        2.312
52................................         48.7         54.5        2.071        2.049        2.214        2.177
53................................         68.6         66.8        2.496        2.202        2.305        2.301
54................................         87.1         85.7        2.642        2.401        2.421        2.462
55................................         58.0         52.4        2.540        2.213        2.347        2.310
56................................         86.9         96.8        0.806        0.817        0.804        0.803
57................................         77.3         86.3        0.704        0.710        0.676        0.699
58................................         78.8         84.5        0.729        0.728        0.690        0.718
59................................         75.6         65.0        0.653        0.637        0.601        0.628
60................................         52.8         56.4        0.597        0.615        0.634        0.606
61................................         69.5         67.9        0.595        0.628        0.646        0.619
62................................         75.9         69.2        0.750        0.750        0.710        0.739
63................................         89.5         91.0        0.649        0.667        0.624        0.658
64................................         67.9         66.4        0.597        0.605        0.625        0.596
65................................         70.0         86.0        0.560        0.566        0.590        0.557
66................................         51.9         53.9        0.578        0.592        0.612        0.583
67................................         70.6         73.1        0.651        0.627        0.642        0.618
68................................         68.0         73.5        0.574        0.603        0.623        0.594
69................................         62.5         70.4        0.577        0.600        0.622        0.591
70................................         59.6         56.2        0.596        0.605        0.624        0.596
71................................         78.8         64.1        0.637        0.642        0.603        0.632
72................................        115.0         82.3        0.611        0.622        0.583        0.613
73................................         78.5         81.6        0.711        0.702        0.670        0.692
74................................         97.9         89.4        0.718        0.714        0.682        0.704

[[Page 59770]]

 
75................................         80.7         85.3        0.656        0.645        0.606        0.636
76................................         69.6         77.5        0.580        0.584        0.609        0.576
77................................         70.8         76.2        0.593        0.574        0.598        0.565
78................................         71.5         73.6        0.558        0.612        0.631        0.603
79................................         87.2         90.8        0.613        0.635        0.599        0.626
80................................         81.7         83.5        0.611        0.614        0.579        0.605
81................................         50.6         57.9        0.598        0.625        0.645        0.616
82................................         81.7         84.5        0.622        0.636        0.594        0.627
83................................         73.6         73.9        0.588        0.611        0.632        0.602
84................................         73.0         80.6        0.580        0.589        0.611        0.580
85................................         67.0         81.0        0.640        0.589        0.611        0.580
86................................         83.8         67.2        0.654        0.649        0.611        0.639
87................................         84.4         74.1        0.644        0.629        0.590        0.620
88................................         89.3         95.6        0.646        0.662        0.618        0.653
89................................         48.2         53.3        0.603        0.606        0.674        0.598
90................................         50.7         57.1        0.535        0.544        0.632        0.536
91................................         80.8         84.3        0.614        0.642        0.606        0.632
92................................         65.1         67.3        0.620        0.634        0.653        0.625
93................................         71.8         76.4        0.557        0.593        0.615        0.584
94................................         59.9         60.4        0.588        0.586        0.607        0.577
95................................         74.6         81.7        0.556        0.564        0.588        0.555
96................................         75.9         80.7        0.669        0.675        0.632        0.665
97................................         55.0         63.1        0.607        0.602        0.622        0.593
98................................         57.8         54.2        0.623        0.626        0.644        0.617
99................................         60.4         53.7        0.596        0.606        0.629        0.597
100...............................         72.0         75.1        0.552        0.592        0.613        0.583
101...............................         53.7         59.6        0.556        0.574        0.598        0.566
102...............................         68.6         72.5        0.620        0.613        0.632        0.604
103...............................         82.3         86.0        0.652        0.658        0.619        0.649
104...............................        130.2         98.4        0.646        0.648        0.602        0.639
105...............................         67.7         78.9        0.621        0.632        0.650        0.623
106...............................        113.0         95.5        0.654        0.666        0.623        0.656
107...............................         64.9         65.5        0.571        0.580        0.603        0.571
108...............................        113.0         95.5        0.654        0.666        0.623        0.656
109...............................         68.6         70.8        0.633        0.672        0.682        0.662
110...............................         68.6         68.6        0.646        0.659        0.670        0.649
111...............................         81.5         87.3        0.713        0.726        0.692        0.715
112...............................         66.0         69.9        0.626        0.634        0.648        0.625
113...............................         67.3         68.7        0.662        0.676        0.684        0.666
114...............................         81.3         81.1        0.689        0.680        0.649        0.670
115...............................         80.1         84.9        0.685        0.666        0.638        0.656
116...............................         82.9         83.7        0.646        0.696        0.662        0.686
117...............................         78.5         70.7        0.725        0.727        0.690        0.716
118...............................        114.4        106.4        0.693        0.673        0.640        0.663
119...............................         90.7         88.9        0.704        0.718        0.683        0.707
120...............................         87.9         68.7        0.699        0.695        0.663        0.685
121...............................         65.1         70.3        0.576        0.593        0.614        0.584
122...............................         65.8         75.5        0.658        0.664        0.674        0.655
123...............................         82.0         84.5        0.639        0.641        0.607        0.631
124...............................         76.5         83.8        0.636        0.632        0.592        0.623
125...............................         78.6         88.2        0.636        0.653        0.612        0.644
126...............................         77.4         68.0        0.689        0.706        0.674        0.696
127...............................        104.9        106.0        0.690        0.714        0.677        0.703
128...............................         75.9         82.5        0.674        0.695        0.657        0.685
129...............................         86.5         88.8        0.676        0.705        0.668        0.695
130...............................         79.7         84.0        0.691        0.711        0.676        0.701
131...............................         61.6         69.0        0.592        0.592        0.610        0.587
132...............................         91.6         87.0        0.613        0.658        0.618        0.644
133...............................         61.1         66.0        0.602        0.605        0.618        0.598
134...............................         73.9         79.6        0.592        0.611        0.625        0.604
135...............................         75.1         73.7        0.647        0.658        0.616        0.644
136...............................         68.4         74.1        0.529        0.552        0.580        0.552
137...............................         67.7         62.3        0.597        0.607        0.620        0.600
138...............................         66.9         72.7        0.529        0.554        0.582        0.554
139...............................         73.5         72.1        0.580        0.581        0.601        0.577
140...............................         68.8         72.0        0.648        0.591        0.607        0.586
141...............................         85.8         81.3        0.715        0.704        0.654        0.683
142...............................         68.1         72.0        0.633        0.643        0.644        0.631
143...............................         84.7         69.6        0.699        0.710        0.657        0.689
144...............................         85.0         69.5        0.700        0.711        0.660        0.690

[[Page 59771]]

 
145...............................         66.5         82.1        0.560        0.666        0.661        0.651
146...............................         92.6         88.7        0.688        0.702        0.651        0.682
147...............................         74.0         77.4        0.682        0.690        0.682        0.672
148...............................         51.2         52.7        0.942        0.957        0.932        0.931
149...............................         45.9         43.4        0.897        0.924        0.921        0.915
150...............................         57.4         49.5        0.922        0.938        0.919        0.922
151...............................         63.3         60.7        0.911        0.950        0.926        0.927
152...............................         54.3         57.3        0.920        0.914        0.903        0.910
153...............................         38.6         42.5        0.897        0.907        0.913        0.907
154...............................         41.4         44.6        0.890        0.865        0.893        0.887
155...............................         57.3         51.8        0.938        0.927        0.912        0.917
156...............................         49.1         46.8        0.898        0.912        0.916        0.910
157...............................         66.4         74.4        0.933        0.925        0.910        0.916
158...............................         64.2         63.0        0.912        0.932        0.915        0.919
159...............................         60.7         60.8        0.910        0.922        0.908        0.914
160...............................         51.5         53.1        0.888        0.903        0.896        0.905
161...............................         55.0         57.0        0.920        0.945        0.923        0.925
162...............................         59.4         61.8        0.926        0.957        0.931        0.931
163...............................         36.5         45.9        0.878        0.949        0.933        0.927
164...............................         52.0         53.8        0.950        0.945        0.923        0.925
165...............................         61.0         56.2        0.930        0.933        0.916        0.920
166...............................         48.0         48.1        0.870        0.896        0.908        0.902
167...............................         60.1         61.3        0.919        0.932        0.915        0.919
168...............................         55.6         52.9        0.929        0.924        0.909        0.915
169...............................         42.1         47.8        0.911        0.917        0.918        0.912
170...............................         51.3         55.8        0.915        0.934        0.916        0.920
171...............................         61.1         66.7        0.907        0.929        0.913        0.918
172...............................         57.0         57.1        0.931        0.934        0.916        0.920
173...............................         58.3         57.3        0.922        0.941        0.921        0.924
174...............................         61.0         62.1        0.910        0.933        0.916        0.920
175...............................         58.3         50.6        0.873        0.856        0.864        0.867
176...............................         61.1         59.9        2.470        2.394        2.448        2.456
177...............................         94.6         93.6        2.439        2.715        2.713        2.716
178...............................         64.1         64.7        3.270        3.223        3.144        3.127
179...............................         78.4         70.2        2.424        2.344        2.444        2.416
180...............................        100.1         96.9        2.137        2.012        2.170        2.147
181...............................         52.3         66.7        2.219        2.266        2.314        2.353
182...............................         66.1         64.5        3.140        3.173        3.103        3.087
183...............................         89.6         91.2        3.330        3.436        3.295        3.299
184...............................         74.8         77.0        2.270        2.193        2.272        2.293
185...............................         89.4         91.0        3.186        3.316        3.208        3.202
----------------------------------------------------------------------------------------------------------------

    In response to the UEF conversion for the NOPR, AHRI commented that 
units tested with the very small, low, and medium draw patterns will 
likely have UEF values less than EF, while units tested with the high 
draw pattern will likely have UEF values greater than EF due to standby 
times. (AHRI, No. 13 at p. 6) Were standby time the only factor 
affecting the difference between EF and UEF, AHRI's argument would have 
some merit. However, in 9 percent of the consumer storage tests, a 
pattern opposite from what AHRI suggested was observed. This empirical 
observation indicates that AHRI's assumptions are not wholly correct. 
AHRI also commented that for most of the electric resistance water 
heater samples, the calculated conversion factor using the WHAM-
regression UEF model does not track with the tested UEF (i.e., some 
values are higher than the test result, others lower). (AHRI, No. 13 at 
p. 5) Further, AHRI stated that for electric resistance models, the 
measured UEF is consistently lower than the measured EF, although the 
amount of difference varies. AHRI stated that the data for units in the 
low-usage bin indicate a very significant miscalculation of the effect 
of the UEF test procedure on those models, and that the converted UEF 
value in most cases is higher than the measured UEF value, which 
suggests that the converted UEF formula is underestimating the effect 
of the uniform energy descriptor test procedure. (AHRI, No. 6 at p. 2) 
AHRI also pointed out that the measured UEFs for low-input (<10,000 
Btu/h) heat pump water heaters were higher than the measured EF, and 
for the one higher-input unit, the measured UEF was lower than the 
measured EF. However, with one exception, the calculated UEF using the 
proposed conversion exhibited the opposite results. (AHRI, No. 13 at p. 
5)
    Rheem commented that several electric storage water heaters (both 
heat pump and non-heat pump) in the medium draw pattern show an 
increased UEF rating as compared to EF in DOE's test results. However, 
Rheem asserted that since the UEF test method has more standby time 
than the EF test method, the resulting UEF would be expected to 
decrease, and stated that it has observed a consistent decrease in the 
UEF of electric storage water heaters in the medium draw bin, as 
compared to the EF rating. (Rheem, No. 11 at pp. 4-5)
    With respect to AHRI's observation that the WHAM-regression model 
does not perfectly reproduce the UEF measurements of every model, DOE 
notes that, as discussed previously, a

[[Page 59772]]

simple conversion formula will not reproduce identically the results 
that one would measure by applying the EF and UEF test methods for each 
and every unit. Yet DOE's task, as required by the statute, is to 
prepare a set of conversion formulas. DOE understands the statute, by 
implication, to contemplate that for any given unit, there may be some 
difference between the formula output and the comparative EF and UEF 
test results.
    AHRI's observation that the measured UEF is consistently less than 
the measured EF for electric resistance storage water heaters in the 
low-draw bin generally still holds for the conversion factor proposed 
in this SNOPR, and as stated above, this behavior is expected. Of the 
13 low-draw-pattern units for which test data are available for the 
SNOPR, the conversion factor predicts a UEF higher than the tested UEF 
in 9 cases, equal to the tested UEF in 3 cases, and lower than the 
predicted UEF in 1 case. DOE reasons that this result is due to the 
large number of medium-draw-pattern units used to derive the conversion 
factor. Similarly, the converted UEF for the one high-draw-pattern 
electric storage water heater is below the tested UEF value. Because 
the regression analysis is conducted across all draw patterns for a 
given class, the result may more heavily favor draw patterns with more 
data present. DOE believes that proposing a separate conversion for 
each draw pattern would eliminate this issue. However, if DOE were to 
propose conversions for each draw pattern, the number of UEF conversion 
equations would increase from 26 to 104. DOE believes a separate 
conversion factor for each draw pattern would add a significant amount 
of complexity to the conversion factor that would not be justified by 
the slight skew toward draw patterns with more units (and therefore 
more test data). DOE also notes that the converted values are not 
always higher than the tested values under the conversions proposed in 
this SNOPR indicating that this effect does not occur consistently for 
all units. Further, Rheem's observation that the consumer electric 
storage medium-draw-pattern testing yields UEFs greater than 
corresponding EF values for some units appears to occur in both the DOE 
and AHRI data sets, suggesting that standby time is not the only 
variable to consider when comparing results from the two test 
procedures. AHRI's observation about the effect of the input rate on 
the difference between measured UEF and EF in the heat pump water 
heater tests based on the NOPR data appears not to hold with the 
addition of the AHRI test data.
    For gas-fired storage water heaters, AHRI commented that in the 
medium-usage bin, the measured UEF is consistently lower than the 
measured EF, but there is no consistent pattern in the difference 
between the measured UEF and the converted UEF. (AHRI, No. 6 at p. 2) 
For gas-fired storage water heaters in the high-usage bin, AHRI stated 
that the measured UEF is consistently higher than the measured EF, and 
there is no consistent relationship between the converted UEF value and 
the measured UEF value. (AHRI, No. 6 at p. 2) AHRI and Rheem commented 
that, for ultra-low NOX gas-fired water heaters, the 
measured UEF for the short models was less than the measured EF and the 
measured UEF for the tall models was greater than the measured EF, but 
that the calculated UEF using the conversion exhibits the opposite 
relationship. AHRI and Rheem suggested the trend requires further test 
data for such units. (AHRI, No. 13 at p. 5; Rheem, No. 11 at p. 7)
    In general, measured UEF values in the very small, low, or medium 
draw patterns will usually be lower than their respective measured EF 
values, and measured UEF values in the high draw patterns will usually 
be higher than their respective measured EF value. Also, this outcome 
(i.e., converted results both higher and lower than the measured 
results for a category of water heater) is what one should expect if 
the conversion is, overall, a reasonable representation of efficiency. 
Therefore, AHRI's comments about the consumer gas-fired storage test 
and conversion data for the medium and high draw pattern reflect the 
expected result of the conversion.
    AHRI and Rheem's comment about the ultra-low NOX short 
comparison of measured EF and UEF seems to still hold with the addition 
of the AHRI test data; that is, the measured UEF for 4 of the 7 short 
models was less than the measured EF, equal to the measured EF for 1 
unit, and greater than the measured EF for 2 units. The measured UEF 
for the tall models was greater than the measured EF in 8 of the 17 
units, and less than the measured EF in the other 9 units. When 
examining the converted UEF values, 5 short units have converted UEFs 
less than the measured EF and 2 that are greater, while the same 
relationship exists in the converted UEF data as was observed in the 
measured UEF data for the tall units. Further, deriving separate 
conversions for short and tall ultra-low NOX water heaters 
decreases the RMSD value by less than 0.0015, which seems like a 
negligible improvement when weighed against the added complexity of an 
additional conversion factor. DOE also notes that it is not aware of an 
industry-accepted consensus for determining whether a water heater is 
``tall'' or ``short,'' which makes implementing a conversion based on 
this factor difficult.
b. Consumer Instantaneous Water Heaters
i. Test Results
    DOE has tested 22 consumer instantaneous water heaters to both the 
EF and UEF test procedures, and AHRI has supplied test data for 36 
additional units of this water heater type.13 14 Table 
III.31 presents the test data used to derive the proposed consumer 
instantaneous water heater conversion factors. DOE notes that 1 of the 
53 gas-fired instantaneous water heaters that were tested is not rated 
to meet the current energy conservation standards (compliance required 
April 16, 2015). However, as discussed in section III.E.2.a.i, DOE 
believes that these data points are valid for the purpose of 
determining the mathematical conversion factors. It is noted that test 
results show measured recovery efficiencies above 100 percent and EFs 
and UEFs above 1 for electric instantaneous units; DOE acknowledges 
that these results appear to violate theoretical limits and believes 
that these results are an artifact of measurement uncertainty. Table 
III.32 shows the water heater attributes by unit described in section 
III.E.1.
---------------------------------------------------------------------------

    \13\ The AHRI submitted test data point CIS-5 was not used 
because the measured input rate was greater than the maximum 
allowable deviation from the rated input rate of 2 percent, 
resulting in an invalid test.
    \14\ If multiple tests were conducted on either the same unit or 
same basic model of a water heater, the results were averaged to 
produce the values reported in this SNOPR. In one instance within 
the AHRI submitted data for consumer instantaneous water heaters, 
three tests were conducted, where two tests were conducted on the 
same unit and another test was conducted on a unit of the same basic 
model. The two tests of the same unit were averaged and this value 
was then averaged with the results of the test of the unit of the 
same basic model.

[[Page 59773]]



                                                                   Table III.31--Consumer Instantaneous Water Heater Test Data
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                    Input rate                      Updated max   Prior recovery
                    CI No.                                  AHRI No.                   Type           (Btu/h)      Prior max GPM        GPM       efficiency (%)        EF              UEF
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1.............................................  N/A.............................             Gas         142,500             3.0             3.4            80.9           0.801           0.800
2.............................................  N/A.............................             Gas         190,800             4.2             4.8            81.4           0.813           0.820
3.............................................  N/A.............................             Gas         120,900             2.7             3.1            82.6           0.828           0.809
4.............................................  N/A.............................             Gas         141,100             3.1             3.6            81.7           0.812           0.823
5.............................................  N/A.............................             Gas         175,800             3.7             4.3            84.5           0.838           0.833
6.............................................  N/A.............................             Gas         178,500             4.1             4.7            83.8           0.838           0.830
7.............................................  N/A.............................             Gas         199,000             4.6             4.9            86.9           0.872           0.841
8.............................................  N/A.............................             Gas         179,900             4.0             4.6            80.3           0.803           0.840
9.............................................  N/A.............................             Gas         180,400             3.9             4.6            85.1           0.852           0.832
10............................................  N/A.............................             Gas         199,200             4.3             5.1            75.0           0.743           0.799
11............................................  N/A.............................             Gas         151,700             3.4             3.9            85.4           0.853           0.813
12............................................  N/A.............................             Gas         199,800             4.8             4.1            93.8           0.932           0.939
13............................................  N/A.............................             Gas         197,200             5.2             5.8            96.7           0.966           0.958
14............................................  N/A.............................             Gas         154,100             4.0             4.5            91.6           0.913           0.925
15............................................  N/A.............................             Gas         201,300             4.9             5.7            88.0           0.851           0.884
16............................................  N/A.............................             Gas         117,800             2.5             2.9            77.7           0.776           0.757
17............................................  N/A.............................             Gas         148,800             3.3             3.7            82.6           0.823           0.811
18............................................  N/A.............................        Electric          33,100             0.9             1.0           101.7           1.018           1.010
19............................................  N/A.............................        Electric           7,800             0.2             0.2           101.2           1.013           0.983
20............................................  N/A.............................        Electric          19,800             0.5             0.6           102.2           1.020           1.006
21............................................  N/A.............................        Electric          26,000             0.7             0.8           102.0           1.019           1.007
22............................................  N/A.............................        Electric          31,000             0.8             0.9           101.5           1.017           0.982
23............................................  1-94............................             Gas         187,800             4.0             4.5            80.2           0.794           0.809
24............................................  1-92, 93........................             Gas         187,900             4.0             4.4            83.0           0.816           0.815
25............................................  CIS-1...........................             Gas         137,700             3.1             3.6            83.6           0.832           0.812
26............................................  CIS-2...........................             Gas         198,300             4.3             5.0            85.0           0.845           0.843
27............................................  CIS-3...........................             Gas         151,600             3.4             3.9            84.8           0.845           0.806
28............................................  CIS-4...........................             Gas         202,100             4.4             5.1            91.7           0.916           0.869
29............................................  CIS-6...........................             Gas         148,400             3.2             3.8            83.4           0.836           0.805
30............................................  CIS-9...........................             Gas         196,000             4.4             5.0            88.7           0.882           0.869
31............................................  1-85............................             Gas         202,300             4.4             5.1            86.3           0.864           0.817
32............................................  1-86............................             Gas         200,400             4.4             5.1            86.3           0.859           0.826
33............................................  1-87............................             Gas         186,500             4.3             4.8            83.9           0.838           0.816
34............................................  1-88............................             Gas         195,700             4.3             5.0            80.8           0.809           0.640
35............................................  1-89............................             Gas         142,900             3.2             3.6            84.6           0.842           0.792
36............................................  1-90............................             Gas         188,500             4.0             4.6            85.3           0.847           0.824
37............................................  1-100...........................             Gas         197,400             4.3             5.5            83.8           0.826           0.818
38............................................  1-101...........................             Gas         141,800             3.1             3.6            83.1           0.831           0.816
39............................................  1-77, 83, 84....................             Gas         151,600             3.5             4.0            87.2           0.874           0.851
40............................................  1-97............................             Gas         198,700             4.8             5.5            98.8           0.975           0.952
41............................................  CIS-7...........................             Gas         195,100             5.1             5.6            97.8           0.978           0.922
42............................................  CIS-8...........................             Gas         150,100             3.7             4.3            95.3           0.951           0.918
43............................................  2-9.............................             Gas         203,200             4.8             5.5            98.2           0.974           0.943
44............................................  2-10............................             Gas         177,200             4.4             5.0            96.8           0.951           0.925
45............................................  2-11............................             Gas         203,500             4.9             5.4            98.1           0.974           0.945
46............................................  2-12............................             Gas         195,100             4.9             5.6            96.7           0.965           0.922
47............................................  2-13............................             Gas         150,100             3.7             4.3            95.3           0.951           0.918
48............................................  1-78............................             Gas         155,000             3.8             4.4            97.4           0.964           0.928
49............................................  1-79............................             Gas         159,400             4.0             4.5            96.1           0.959           0.921
50............................................  1-80............................             Gas         176,900             4.3             4.9            96.3           0.947           0.920
51............................................  1-81............................             Gas         176,700             4.3             4.9            97.9           0.966           0.933
52............................................  1-82............................             Gas         183,200             4.5             5.2            96.5           0.957           0.919
53............................................  1-91............................             Gas         120,500             3.1             3.5            94.1           0.937           0.910
54............................................  1-98............................             Gas         182,100             4.1             5.1            90.8           0.908           0.911
55............................................  1-99............................             Gas         197,000             5.0             5.0            95.3           0.935           0.924
56............................................  1-102...........................             Gas         122,300             2.9             3.4            91.4           0.915           0.883
57............................................  1-103...........................             Gas         183,000             4.4             4.8            92.1           0.914           0.901
58............................................  1-104...........................             Gas         121,100             2.7             3.2            91.5           0.910           0.864
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


      Table III.32--Consumer Instantaneous Water Heater Attributes
------------------------------------------------------------------------
             CI No.               NOX emission level      Condensing
------------------------------------------------------------------------
1...............................  Low...............  No.
2...............................  Low...............  No.
3...............................  Low...............  No.
4...............................  Low...............  No.
5...............................  Ultra-Low.........  No.
6...............................  Ultra-Low.........  No.
7...............................  Ultra-Low.........  No.

[[Page 59774]]

 
8...............................  Ultra-Low.........  No.
9...............................  Ultra-Low.........  No.
10..............................  Ultra-Low.........  No.
11..............................  Ultra-Low.........  No.
12..............................  Ultra-Low.........  Yes.
13..............................  Ultra-Low.........  Yes.
14..............................  Ultra-Low.........  Yes.
15..............................  Ultra-Low.........  Yes.
16..............................  Low...............  No.
17..............................  Low...............  No.
18..............................  N/A...............  N/A.
19..............................  N/A...............  N/A.
20..............................  N/A...............  N/A.
21..............................  N/A...............  N/A.
22..............................  N/A...............  N/A.
23..............................  Low...............  No.
24..............................  Low...............  No.
25..............................  Ultra-Low.........  No.
26..............................  Ultra-Low.........  No.
27..............................  Ultra-Low.........  No.
28..............................  Ultra-Low.........  No.
29..............................  Ultra-Low.........  No.
30..............................  Ultra-Low.........  No.
31..............................  Ultra-Low.........  No.
32..............................  Ultra-Low.........  No.
33..............................  Ultra-Low.........  No.
34..............................  Ultra-Low.........  No.
35..............................  Ultra-Low.........  No.
36..............................  Ultra-Low.........  No.
37..............................  Ultra-Low.........  No.
38..............................  Ultra-Low.........  No.
39..............................  Ultra-Low.........  No.
40..............................  Low...............  Yes.
41..............................  Ultra-Low.........  Yes.
42..............................  Ultra-Low.........  Yes.
43..............................  Ultra-Low.........  Yes.
44..............................  Ultra-Low.........  Yes.
45..............................  Ultra-Low.........  Yes.
46..............................  Ultra-Low.........  Yes.
47..............................  Ultra-Low.........  Yes.
48..............................  Ultra-Low.........  Yes.
49..............................  Ultra-Low.........  Yes.
50..............................  Ultra-Low.........  Yes.
51..............................  Ultra-Low.........  Yes.
52..............................  Ultra-Low.........  Yes.
53..............................  Ultra-Low.........  Yes.
54..............................  Ultra-Low.........  Yes.
55..............................  Ultra-Low.........  Yes.
56..............................  Ultra-Low.........  Yes.
57..............................  Ultra-Low.........  Yes.
58..............................  Ultra-Low.........  Yes.
------------------------------------------------------------------------

ii. Conversion Factor Results
    As stated in section III.C.4.a, DOE developed an analytical model 
that DOE proposes to use to convert the prior measured values of 
maximum GPM rating for consumer instantaneous water heaters to measured 
values under the uniform efficiency descriptor test procedure. DOE also 
developed an analytical method to estimate the change in prior measured 
values of energy factor under the energy factor test procedure to 
measured values of uniform energy factor under the uniform efficiency 
descriptor test procedure. Along with this analytical model, step 
regression and combined analytical model-regression approaches were 
conducted. The results of the analytical model, step regression, and 
combined analytical model-regression approaches for the maximum GPM and 
UEF conversions are presented in Table III.34. For the maximum GPM 
conversions, the RMSD for the three approaches are 0.24, 0.23, and 
0.23, respectively. For the UEF conversions, the three approaches have 
RMSD of 0.035, 0.028, and 0.027, respectively. DOE has decided to 
continue to propose to use the analytical model approach to calculate 
the consumer instantaneous maximum GPM conversion factor owing to the 
fact that the analytical model approach predicts the resultant data 
very closely and that it will broadly apply to those units not tested. 
DOE has also decided to continue to propose to use the combined 
analytical model-regression approach to convert from EF to UEF since 
the RMSDs are the lowest observed, and it has concluded that the use of 
the model and regression will capture key effects that may not be 
captured with either approach by itself. The resulting conversion 
factors for both maximum GPM and UEF are shown in Table III.33. In the 
equations in Table III.33, Max GPMP is the maximum GPM based 
on the prior DOE test procedure and UEFmodel is the 
predicted UEF determined using the analytical model, described in 
section III.C.4.c.

     Table III.33--Proposed Consumer Instantaneous Conversion Factor
                                Equations
------------------------------------------------------------------------
             Product class                      Conversion factor
------------------------------------------------------------------------
All Consumer Instantaneous.............  New Max GPM = 1.1461 x Max GPMP
Gas-fired Instantaneous................  New UEF = 0.1006 + 0.8622 x
                                          UEFmodel
Electric Instantaneous.................  New UEF = 0.9847 x UEFmodel
------------------------------------------------------------------------


                                             Table III.34--Consumer Instantaneous Conversion Factor Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Combined                                            Combined
                                                   Tested max   Analytical   Regression  Analytical-                Analytical   Regression  Analytical-
                     CI No.                           GPM        max GPM      max GPM     Regression   Tested UEF      UEF          UEF       Regression
                                                                                           Max GPM                                               UEF
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................         3.44         3.39         3.49         3.49        0.800        0.804        0.791        0.794
2...............................................         4.81         4.85         4.80         4.80        0.820        0.810        0.802        0.799
3...............................................         3.11         3.09         3.21         3.21        0.809        0.820        0.814        0.808
4...............................................         3.61         3.57         3.64         3.64        0.823        0.811        0.801        0.800
5...............................................         4.31         4.21         4.22         4.22        0.833        0.841        0.823        0.825
6...............................................         4.71         4.68         4.64         4.64        0.830        0.834        0.823        0.820
7...............................................         4.87         5.29         5.18         5.18        0.841        0.865        0.852        0.846
8...............................................         4.59         4.60         4.57         4.57        0.840        0.799        0.793        0.790
9...............................................         4.61         4.50         4.48         4.48        0.832        0.847        0.835        0.831
10..............................................         5.07         4.93         4.86         4.86        0.799        0.747        0.741        0.745
11..............................................         3.89         3.85         3.90         3.90        0.813        0.847        0.836        0.831
12..............................................         4.11         5.50         5.37         5.37        0.939        0.933        0.904        0.905
13..............................................         5.81         5.94         5.77         5.77        0.958        0.962        0.934        0.930
14..............................................         4.48         4.56         4.53         4.53        0.925        0.912        0.888        0.887
15..............................................         5.70         5.62         5.48         5.48        0.884        0.876        0.834        0.856
16..............................................         2.88         2.85         3.01         3.01        0.757        0.772        0.770        0.766
17..............................................         3.67         3.73         3.79         3.79        0.811        0.821        0.810        0.808
18..............................................         0.99         1.00         1.00         1.00        1.010        1.013        1.000        0.997
19..............................................         0.24         0.24         0.24         0.24        0.983        1.008        0.981        0.993
20..............................................         0.60         0.59         0.60         0.60        1.006        1.018        1.007        1.003
21..............................................         0.80         0.78         0.78         0.78        1.007        1.016        1.003        1.001

[[Page 59775]]

 
22..............................................         0.93         0.94         0.94         0.94        0.982        1.011        0.997        0.996
23..............................................         4.50         4.61         4.57         4.57        0.809        0.798        0.785        0.789
24..............................................         4.40         4.57         4.54         4.54        0.815        0.826        0.804        0.813
25..............................................         3.56         3.55         3.63         3.63        0.812        0.830        0.818        0.817
26..............................................         4.95         4.97         4.90         4.90        0.843        0.846        0.829        0.830
27..............................................         3.94         3.93         3.97         3.97        0.806        0.842        0.829        0.827
28..............................................         5.10         5.00         4.92         4.92        0.869        0.913        0.890        0.888
29..............................................         3.80         3.67         3.73         3.73        0.805        0.828        0.821        0.814
30..............................................         5.05         4.99         4.91         4.91        0.869        0.883        0.861        0.862
31..............................................         5.14         5.06         4.98         4.98        0.817        0.859        0.845        0.841
32..............................................         5.07         5.01         4.93         4.93        0.826        0.859        0.841        0.841
33..............................................         4.84         4.92         4.85         4.85        0.816        0.835        0.823        0.821
34..............................................         4.96         4.93         4.86         4.86        0.640        0.804        0.798        0.794
35..............................................         3.63         3.64         3.71         3.71        0.792        0.840        0.827        0.825
36..............................................         4.57         4.63         4.59         4.59        0.824        0.849        0.831        0.833
37..............................................         5.52         4.93         4.86         4.86        0.818        0.834        0.813        0.820
38..............................................         3.62         3.50         3.58         3.58        0.816        0.825        0.817        0.812
39..............................................         4.00         3.96         4.00         4.00        0.851        0.868        0.855        0.849
40..............................................         5.54         5.47         5.34         5.34        0.952        0.983        0.941        0.948
41..............................................         5.60         5.85         5.68         5.68        0.922        0.973        0.944        0.939
42..............................................         4.30         4.24         4.25         4.25        0.918        0.948        0.921        0.918
43..............................................         5.50         5.50         5.37         5.37        0.943        0.977        0.941        0.943
44..............................................         5.00         5.04         4.96         4.96        0.925        0.963        0.921        0.931
45..............................................         5.40         5.62         5.48         5.48        0.945        0.976        0.941        0.942
46..............................................         5.60         5.62         5.48         5.48        0.922        0.962        0.933        0.930
47..............................................         4.30         4.24         4.25         4.25        0.918        0.948        0.921        0.918
48..............................................         4.36         4.34         4.34         4.34        0.928        0.969        0.932        0.936
49..............................................         4.52         4.54         4.51         4.51        0.921        0.956        0.928        0.925
50..............................................         4.94         4.92         4.85         4.85        0.920        0.958        0.917        0.926
51..............................................         4.92         4.91         4.84         4.84        0.933        0.974        0.934        0.940
52..............................................         5.18         5.20         5.11         5.11        0.919        0.960        0.926        0.928
53..............................................         3.50         3.54         3.62         3.62        0.910        0.934        0.909        0.906
54..............................................         5.10         4.74         4.70         4.70        0.911        0.904        0.884        0.880
55..............................................         5.05         5.74         5.59         5.59        0.924        0.948        0.907        0.918
56..............................................         3.37         3.30         3.41         3.41        0.883        0.907        0.890        0.882
57..............................................         4.80         5.04         4.96         4.96        0.901        0.917        0.889        0.891
58..............................................         3.20         3.09         3.22         3.22        0.864        0.908        0.885        0.883
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In response to the April 2015 NOPR, AHRI commented that for gas-
fired instantaneous water heaters tested by DOE, most condensing units 
had measured UEFs that were greater than the EF, but the calculated UEF 
using the mathematical conversion for these units in all cases was less 
than the tested UEF. (AHRI, No. 13 at p. 6) NEEA commented that the UEF 
rating comparison results are so scattered as to strongly suggest that 
there are factors, which differ from one water heater to another, 
missing from the current analytical approach, or that one or more of 
DOE's assumptions or approximations used in the analytical approach are 
not valid for every water heater. NEEA suggested that a likely source 
of error may be in the methods used to estimate the amount of energy 
absorbed by the water heater in any given firing cycle, or the related 
estimates of the impact of the time between firing cycles on this 
factor. NEEA also commented that the conversion for gas-fired 
instantaneous water heaters consistently underrates the UEF of 
condensing water heaters and seems unable to predict reliably the 
measured UEF of any non-condensing models. (NEEA, No. 15 at p. 6)
    In response, DOE notes that the relationship between measured UEF 
and EF is not a result of the conversion, but rather how water heaters 
are performing when tested to the UEF test procedure. In the set of 
data used for this rulemaking, DOE observes that 19 of the 23 
condensing units have a measured UEF less than the measured EF. AHRI 
and NEEA commented that the conversion for condensing gas-fired 
instantaneous water heaters underrates the UEF. DOE notes that with the 
new test data and conversion factors, 7 of the condensing units have 
converted UEFs greater than the measured, 9 are less than, and 7 are 
equal to, after rounding to the second decimal place, suggesting that 
the proposed conversion factor contained in this SNOPR is overall, a 
more accurate fit to the test data than the conversion factor proposed 
in the NOPR. Further, the RMSD values for the NOPR and SNOPR 
conversions for the current set of condensing units are 0.063 and 
0.017, respectively. These results indicate that the SNOPR conversion 
factors are better predictors of actual performance. Regarding NEEA's 
statement that the conversion is unable to predict reliably the 
measured UEF of non-condensing models, DOE notes that the RMSD value is 
0.034 when applied for just non-condensing units, as compared to the 
RMSD value of 0.017 when applied to just condensing units, which 
indicates that the conversion equation for gas-fired instantaneous 
water heaters does fit the non-condensing data points almost as well as 
it fits the condensing data points. However, DOE notes that the new 
conversion equation for non-condensing gas-fired instantaneous water 
heaters produced converted UEF values above the measured UEF values for 
11 units,

[[Page 59776]]

below the measured UEF values for 11 units, and equal to for 8 units, 
when rounded to the second decimal place, suggesting the conversion is 
representing the non-condensing category as well as can be expected, 
given the variance in the non-condensing test data, and is not skewed 
toward over- or under-predicting the UEF of these units. Further, when 
separate conversion equations are derived for condensing and non-
condensing gas-fired instantaneous water heaters, the RMSD values for 
non-condensing and condensing instantaneous water heaters only improve 
by 0.003 and 0.001, respectively. DOE has tentatively determined that 
this improvement is negligible when weighed against the added 
complexity of an additional conversion factor. As stated in section 
III.E.1, DOE tentatively considers a change in RMSD to be negligible if 
it is less than one unit (0.01 for EF and UEF, 0.1 for maximum GPM, and 
1.0 for first-hour rating). In this case, 0.003 and 0.001 are less than 
0.01 and would be unlikely to have a noticeable effect when UEF is 
rounded to the nearest 0.01 per the reporting requirements in 10 CFR 
429.17. NEEA's suggestions about improving the instantaneous analytical 
conversion were previously discussed in section III.C.4.c of this 
notice.
c. Residential-Duty Commercial Storage Water Heaters
i. Test Results
    DOE has tested 8 residential-duty commercial storage water heaters 
to both the thermal efficiency and standby loss and UEF test 
procedures, and AHRI has supplied test data for 12 additional units of 
this kind of water heater.\15\ Table III.35 below presents the test 
data used to derive the residential-duty commercial storage water 
heater conversion factors. Table III.36 shows the water heater 
attributes by unit described in section III.E.1.
---------------------------------------------------------------------------

    \15\ If multiple tests were conducted on either the same unit or 
same basic model of a water heater, the results were averaged to 
produce the values reported in this SNOPR.

                                                                Table III.35--Residential-Duty Commercial Water Heater Test Data
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                      Thermal
                 RDS No                             AHRI No                      Type                 Storage       Input  rate     efficiency     Standby  loss   Updated  FHR         UEF
                                                                                                   volume  (gal)      (Btu/h)           (%)           (Btu/h)          (gal)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1.......................................  N/A.......................  Gas.......................            72.9          75,600            74.1          1007.0           107.4           0.612
2.......................................  N/A.......................  Gas.......................            48.3          76,500            93.6           328.0           137.0           0.816
3.......................................  N/A.......................  Gas.......................            93.7          78,900            80.4          1178.2           109.8           0.514
4.......................................  N/A.......................  Gas.......................            70.9          76,900            82.8           580.2           156.4           0.710
5.......................................  N/A.......................  Gas.......................            94.9          83,700            80.0          1389.9           159.2           0.524
6.......................................  N/A.......................  Gas.......................            69.6          75,600            76.9          1407.2           130.0           0.505
7.......................................  N/A.......................  Oil.......................            50.3         140,000            76.7           908.2           134.8           0.617
8.......................................  N/A.......................  Gas.......................            48.4          75,500            89.5           348.3           114.9           0.722
9.......................................  1-105.....................  Gas.......................            93.1          75,200            80.1          1163.3           140.9           0.561
10......................................  2-14......................  Gas.......................            49.0          76,800            97.3           150.0           151.1           0.908
11......................................  2-15......................  Gas.......................            49.0          76,800            97.3           150.0           156.8           0.891
12......................................  1-122.....................  Gas.......................            71.3          79,600            82.7           789.0           131.0           0.650
13......................................  1-120.....................  Gas.......................            49.0          76,800            97.3           150.0           154.0           0.907
14......................................  1-114, 115................  Gas.......................            48.3          75,100            92.6           290.5           119.1           0.877
15......................................  1-106, 107................  Gas.......................            70.8          74,600            80.0          1052.0           113.8           0.625
16......................................  1-110, 111................  Gas.......................            71.1          75,100            81.0           921.0           107.6           0.642
17......................................  1-108, 109................  Gas.......................            95.0          74,000            80.5          1064.5           140.0           0.596
18......................................  1-112, 113................  Gas.......................            94.9          74,700            81.5          1063.0           125.9           0.587
19......................................  1-116, 117................  Gas.......................            49.4         101,300            96.5           422.5           109.9           0.865
20......................................  1-118, 119................  Gas.......................            74.2         101,400            96.0           408.5           174.0           0.842
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


                                            Table III.36--Residential-Duty Commercial Water Heater Attributes
--------------------------------------------------------------------------------------------------------------------------------------------------------
               RDS No                  NOX Emission level          Condensing              Vent type            Short or Tall         Standing Pilot?
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................  Low...................  No....................  Power................  Tall.................  Yes.
2..................................  Low...................  Yes...................  Power................  Short................  No
3..................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
4..................................  Standard..............  No....................  Power................  Tall.................  No
5..................................  Ultra-Low.............  No....................  Atmospheric..........  Not Specified........  Yes.
6..................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
7..................................  N/A...................  N/A...................  N/A..................  Short................  N/A.
8..................................  Low...................  Yes...................  Power................  Tall.................  No
9..................................  Low...................  No....................  Atmospheric..........  Tall.................  Yes.
10.................................  Low...................  Yes...................  Power................  Not Specified........  No
11.................................  Low...................  Yes...................  Power................  Not Specified........  No
12.................................  Low...................  Yes...................  Power................  Tall.................  No
13.................................  Not Specified.........  Yes...................  Power................  Not Specified........  No

[[Page 59777]]

 
14.................................  Low...................  Yes...................  Power................  Tall.................  No
15.................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
16.................................  Standard..............  No....................  Atmospheric..........  Tall.................  Yes.
17.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
18.................................  Ultra-Low.............  No....................  Atmospheric..........  Tall.................  Yes.
19.................................  Ultra-Low.............  Yes...................  Power................  Tall.................  No
20.................................  Ultra-Low.............  Yes...................  Power................  Tall.................  No
--------------------------------------------------------------------------------------------------------------------------------------------------------

ii. Conversion Factor Results
    As stated in section III.C.4.b, DOE is not aware of an analytical 
model to convert the represented values of thermal efficiency and 
standby loss under the prior commercial test procedure to estimate the 
represented value of first-hour rating under the new test procedure. 
Therefore, DOE proposes to use the step regression method described in 
section III.C.2 along with the best combination of water heater 
attributes to determine the first-hour rating conversion factor shown 
in Table III.37. The next step in the conversion is to determine which 
draw pattern is to be applied to convert to UEF. After the first-hour 
rating under the uniform efficiency descriptor is determined through 
the conversion factor, the value can be applied to determine the 
appropriate draw pattern bin (i.e., very small, low, medium, or high) 
using Table 1 of the uniform efficiency descriptor test procedure. 10 
CFR 430, subpart B, appendix E, section 5.4.1. With the draw bin known, 
the UEF value based on the analytical model can be calculated using the 
process described in section III.C.4 of this document. The analytical 
results, along with the results of the step regression and the 
analytical regression, are presented in Table III.38 and have RMSD 
values of 0.032, 0.029, and 0.032, respectively. DOE proposes to use 
the combined analytical-regression approach to calculate the 
residential-duty commercial storage water heater conversion factor 
because the RMSD value is within 0.003 of that of the regression and 
the use of the analytical portion of the conversion will likely apply 
better to units that have not been tested. The resulting equations for 
determining the UEF of residential-duty commercial storage water 
heaters are presented in Table III.37. In the equations in Table 
III.37, Vr is the rated volume, and Et is the 
thermal efficiency in fractional form (e.g., 0.85 instead of 85 (%)). 
UEFrd is the result of the analytical conversion, described 
in section III.C.4.c. For these regressions, DOE decided to group both 
oil-fired and gas-fired water heaters because of the lack of oil-fired 
water heaters identified.

  Table III.37--Proposed Residential-Duty Commercial Storage Conversion
                            Factor Equations
------------------------------------------------------------------------
             Product class                      Conversion factor
------------------------------------------------------------------------
All Residential-Duty Commercial Storage  New FHR = -35.8233 + 0.4649 x
 Water Heaters.                           Vr + 160.5089 x Et
                                         New UEF = -0.0022 + 1.0002 x
                                          UEFrd
------------------------------------------------------------------------


                                          Table III.38--Residential-Duty Commercial Storage Conversion Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Analytical-
                         RDS No.                            Tested FHR    Regression FHR    Tested UEF    Analytical UEF  Regression UEF    Regression
                                                               (gal)           (gal)                                                            UEF
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.......................................................           107.4           117.0           0.612           0.567           0.559           0.565
2.......................................................           137.0           136.9           0.816           0.830           0.831           0.828
3.......................................................           109.8           136.8           0.514           0.578           0.567           0.576
4.......................................................           156.4           130.1           0.710           0.691           0.700           0.689
5.......................................................           159.2           136.7           0.524           0.548           0.527           0.546
6.......................................................           130.0           120.0           0.505           0.532           0.509           0.530
7.......................................................           134.8           110.7           0.617           0.594           0.626           0.592
8.......................................................           114.9           130.3           0.722           0.793           0.798           0.790
9.......................................................           140.9           136.0           0.561           0.579           0.566           0.577
10......................................................           151.1           143.2           0.908           0.918           0.890           0.916
11......................................................           156.8           143.2           0.891           0.918           0.890           0.916
12......................................................           131.0           130.1           0.650           0.651           0.662           0.649
13......................................................           154.0           143.2           0.907           0.918           0.890           0.916
14......................................................           119.1           135.2           0.877           0.833           0.830           0.831
15......................................................           113.8           125.5           0.625           0.594           0.594           0.592
16......................................................           107.6           127.3           0.642           0.620           0.625           0.617
17......................................................           140.0           137.5           0.596           0.595           0.585           0.593
18......................................................           125.9           139.1           0.587           0.601           0.593           0.599
19......................................................           109.9           142.0           0.865           0.825           0.843           0.823
20......................................................           174.0           152.8           0.842           0.825           0.832           0.823
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In response to the NOPR, AHRI stated that for gas-fired 
residential-duty commercial storage water heaters, all the measured UEF 
results are higher than the converted UEF values using the mathematical 
conversion, and the commenters added that the magnitude of the 
difference seems to track with the volume and thermal efficiency of the 
water heater. (AHRI, No. 6 at p. 2) Bradford White stated that its 
results show that both the UEF and FHR are largely underestimated for 
residential-duty commercial gas-fired water heaters when using the 
conversion factors.

[[Page 59778]]

(Bradford White, No. 14 at p. 2) NEEA stated that for residential-duty 
commercial water heaters, there is so little correlation between the 
FHR and UEF calculated from the mathematical conversions and the 
measured values from testing that it is not possible at this point to 
use an analytical approach for determining either of these values. 
(NEEA, No. 15 at p. 6) NEEA elaborated that it is also not clear at 
this point that more testing (more sample models) would be helpful, as 
NEEA believes there are some missing variables/factors that are not 
being taken into account in the analytical methodologies. NEEA 
tentatively concluded that these water heaters will have to be tested 
in the near term in order to produce represented values of FHR and UEF 
that will match the represented values later when all water heaters 
must be re-certified based on tested values. (NEEA, No. 15 at p. 6)
    In response to AHRI and Bradford White's comment about the gas-
fired storage conversion underrating the UEF, DOE notes that under the 
conversion factor proposed in this SNOPR, there are a similar number of 
gas-fired residential-duty commercial units where the converted UEF is 
either higher or lower than the measured UEF,\16\ which suggests that 
the new conversion is a better representation of the test data than was 
proposed in the NOPR. Further, the RMSD values for the NOPR and SNOPR 
conversions with the current data set are 0.068 and 0.032, 
respectively. In response to NEEA comments, DOE notes that the 
analytical method was updated based on other commenters' suggestions, 
and that the resulting new conversion tracks better with the measured 
data than the conversion factor equation proposed in the NOPR.
---------------------------------------------------------------------------

    \16\ Of the 20 residential-duty commercial units tested, 9 had a 
UEF value predicted by the conversion equation that was lower than 
the measured UEF; 7 units had a predicted UEF that was higher than 
the measured UEF, and 4 units had a predicted UEF that was equal to 
the measured UEF, after rounding to the second decimal place.
---------------------------------------------------------------------------

d. Residential-Duty Commercial Instantaneous Water Heaters
    As discussed in section III.B, DOE did not propose a mathematical 
conversion for residential-duty commercial gas-fired instantaneous 
water heaters in the April 2015 NOPR. The definition of residential-
duty commercial water heater applies to commercial equipment and 
specifically excludes gas-fired instantaneous water heaters with an 
input rating above 200,000 Btu/h. 10 CFR 431.102. As defined in EPCA, 
gas-fired instantaneous water heaters with an input rating at or below 
200,000 Btu/h are consumer products, not commercial equipment. (42 
U.S.C. 6291(27)(B)) As such, the definition of residential-duty 
commercial water heater definition precludes all gas-fired 
instantaneous water heaters from being so defined.
    DOE has tentatively concluded a mathematical conversion factor and 
standard denominated in UEF are necessary for residential-duty 
commercial electric instantaneous water heaters. DOE tested 1 
residential-duty commercial electric instantaneous water heater to the 
test procedure that was proposed in the UEF test procedure NOPR. 78 FR 
66202 (Nov. 4, 2013). The maximum GPM conversion is based on a 
regression, and DOE included this data point for the residential-duty 
commercial electric instantaneous unit in that conversion without the 
need for further testing, because there were no substantial changes to 
the maximum GPM test for electric instantaneous water heaters between 
the UEF test procedure NOPR and final rule. Because of the small amount 
of data available and the relative similarity between units above and 
below the 12 kW cut-off between consumer and residential-duty 
commercial water heaters, DOE also used the 5 consumer electric 
instantaneous water heaters that were tested (see section III.E.2.b) in 
the development of the mathematical conversion factor for the maximum 
GPM of residential-duty commercial electric instantaneous water 
heaters. Table III.39 below presents the residential-duty commercial 
electric instantaneous water heater test data used to develop the 
conversion factors.

  Table III.39--Residential-Duty Commercial Instantaneous Water Heater
                                Test Data
------------------------------------------------------------------------
                                           Input
                RDI No.                     rate     Updated      UEF
                                          (Btu/h)    max GPM
------------------------------------------------------------------------
1......................................     83,600       2.48      0.948
------------------------------------------------------------------------

    DOE examined potential parameters for predicting the maximum GPM 
rating of residential-duty commercial electric instantaneous water 
heaters. Given the de minimis losses from electric heating elements, 
and the de minimis standby losses associated with tankless water 
heaters, DOE believes that it is appropriate to assume that the 
delivery capacity would be heavily dependent on the input rating for 
electric instantaneous water heaters. DOE examined the predicted 
maximum GPM as a function of input rate, and developed an equation 
which results in an RMSD of 0.009 gpm. DOE proposes to use the 
following equation as the mathematical conversion factor for max GPM, 
where Q is input rate in kBtu/h.

New Max GPM = 0.0146 + 0.0295 * Q

    DOE has tentatively determined that the UEF value shown in Table 
III.39, which is a result of the UEF test procedure NOPR is not 
appropriate for use in a regression based conversion. As described in 
section III.C.4.c.iv, DOE has proposed an analytical method for 
determining the UEF conversion, and as such, this test point was not 
necessary to develop the UEF conversion. DOE proposes to use the 
analytical method described in section III.C.4.c.iv as the conversion 
for residential-duty commercial electric instantaneous water heaters.
e. Grid-Enabled Storage Water Heaters
    Grid-enabled water heaters have a rated storage volume above 75 
gallons and use electric resistance elements to heat the stored water. 
At the time of its analysis for this notice, DOE was unable to find 
grid-enabled water heaters available on the market which meet the 
definition of ``grid-enabled water heater'' \17\ as set forth in EEIA 
2015. As a result, DOE does not have any test data for grid-enabled 
water heaters specifically. However, DOE does have a large set of data 
for electric resistance storage water heaters, which DOE believes would 
have similar energy consumption-related characteristics to grid-enabled 
water heaters, aside from the differences in stored volume. DOE has 
conducted testing of 18 consumer electric storage water heaters, which 
use electric resistance elements and were

[[Page 59779]]

tested to both the EF and UEF test procedures, and AHRI has supplied 
test data for 27 additional units of this water heater type. DOE 
believes that the electric resistance technology used in grid-enabled 
water heaters to heat water would be similar enough to the technology 
used in the less than or equal to 55 gallon class of consumer electric 
water heaters to be applicable in the derivation of the grid-enabled 
conversion and energy conservation standard derivation. Similarly, the 
insulation type and thickness in grid-enabled water heaters is expected 
to be the same as that currently used in electric storage water heaters 
with storage volumes less than or equal to 55 gallons. Therefore, DOE 
used the same test data to derive the grid-enabled consumer storage 
water heater conversion factors as was used to derive the consumer 
electric storage water heater conversion factor.
---------------------------------------------------------------------------

    \17\ Grid-enabled water heater means an electric resistance 
water heater that--
    (1) Has a rated storage tank volume of more than 75 gallons;
    (2) Is manufactured on or after April 16, 2015;
    (3) has: (i) An energy factor of not less than 1.061 minus the 
product obtained by multiplying--(a) the rated storage volume of the 
tank, expressed in gallons, and (b) 0.00168; or (2) an equivalent 
alternative standard prescribed by the Secretary and developed 
pursuant to 42 U.S.C. 6295(e)(5)(E);
    (4) Is equipped at the point of manufacture with an activation 
lock and;
    (5) Bears a permanent label applied by the manufacturer that--
    (i) Is made of material not adversely affected by water;
    (ii) Is attached by means of non-water-soluble adhesive; and
    (iii) Advises purchasers and end-users of the intended and 
appropriate use of the product with the following notice printed in 
16.5 point Arial Narrow Bold font: ``IMPORTANT INFORMATION: This 
water heater is intended only for use as part of an electric thermal 
storage or demand response program. It will not provide adequate hot 
water unless enrolled in such a program and activated by your 
utility company or another program operator. Confirm the 
availability of a program in your local area before purchasing or 
installing this product.''
    (42 U.S.C. 6295(e)(6)(A)(ii))
---------------------------------------------------------------------------

    For the first-hour rating conversion, the only conversion method 
available is the regression approach. Therefore, the data set of 
electric resistance consumer electric storage water heaters was used to 
derive the following equation:

New FHR = 9.2827 + 0.8092 x FHRP

    As with electric storage water heaters with storage volumes less 
than 55 gallons, DOE used the hybrid approach of using both the WHAM 
equation and a regression to calculate the UEF. Because no grid-enabled 
water heater products are available on the market, DOE applied the 
regression equations derived using the electric storage water heaters 
with storage volumes less than 55 gallons since the technology employed 
is very similar. DOE is proposing to use the following conversion 
equations to determine the UEF (shown as ``New UEF'' in the equation):
[GRAPHIC] [TIFF OMITTED] TP30AU16.037


    DOE considered simply using the WHAM equation for the conversion of 
grid-enabled water heaters, but the inclusion of the regression step 
makes the corresponding energy conservation standards (discussed in 
III.E.3) more consistent with those developed for electric storage 
water heaters with storage volumes at or below 55 gallons, which DOE 
believes are very similar products at lower storage volumes. DOE seeks 
comment on its method of applying the regression for electric storage 
water heaters with storage volumes at or below 55 gallons in developing 
the conversion equation for grid-enabled water heaters. This is 
identified as issue 1 in section V.B, ``Issues on Which DOE Seeks 
Comment.''
3. Energy Conservation Standard Derivation
    After developing the mathematical conversion factors to convert 
from the prior tested values under the EF metric to the tested values 
under the UEF metric, the next step is to translate the energy 
conservation standards to be in terms of UEF. In the April 2015 NOPR 
analysis, DOE investigated several possible methods to determine the 
appropriate energy conservation standards in terms of UEF, and sought 
comments on the various approaches. 80 FR 20116, 20136-38 (April 14, 
2015). DOE ultimately proposed using the ``percent difference'' method, 
which would have updated the minimum standards by first calculating the 
percent difference between the prior EF rating and standard for each 
model on the market, and then applying that percent difference to the 
estimated UEF (based on the conversion factor) to determine the new 
minimum UEF requirement that maintains the same stringency. However, 
because the ``percent difference'' method was based on actual water 
heaters from the CCMS and AHRI directories, the method could only 
directly be applied to categories that had water heaters in them. Thus, 
DOE had to extrapolate standards from similar classes for categories 
where there were no models on the market, such as the consumer gas-
fired storage water heaters greater than 55 gallons category. For this 
SNOPR, DOE has developed a new methodology that it proposes for 
translating the energy conservation standards to UEF, which DOE 
believes would improve the results of the standards translation. DOE 
has termed this new approach as the ``representative model'' method, 
which consists of the following steps for determining the minimum UEF 
standard:
    1. Using the CCMS and AHRI directories, for minimally-compliant 
models, determine the unique rated storage volumes available on the 
market prior to July 13, 2015 (the date on which DOE's requirement that 
rated storage volume equal the mean of the measured storage volume was 
effective; see section III.E.3.a).
    2. For each rated storage volume identified in step 1, find average 
values of conversion factor inputs (i.e., input rating and recovery 
efficiency for consumer water heaters (except consumer heat pump water 
heaters), and input rating for residential-duty commercial water 
heaters) for minimally-compliant models in each product class. (For 
product classes where no minimally-compliant models exist on the 
market, DOE used other methods to estimate the characteristics of 
minimally-compliant models, as discussed in detail subsequently.)
    3. Calculate the energy conservation standard (in terms of EF for 
consumer water heaters and TE/SL for residential-duty commercial water 
heaters (with input rate for determining standards found from step 2)) 
for each product class based on the rated storage volume, as reported 
in the CCMS and AHRI directories at the time of this analysis (before 
DOE's requirement that rated storage volume equal the mean of the 
measured storage volume was effective).
    4. Using applicable average values for conversion factor inputs 
determined in step 2 and the applicable minimum energy conservation 
standards calculated in step 3, calculate the equivalent UEF for 
minimally-compliant models at each discrete rated storage volume 
(determined in step 1) using the appropriate conversion factor for the 
product class.
    5. Adjust the rated storage volumes to estimate the rated storage 
volume that would reflect DOE's requirement at 10 CFR 
429.17(a)(1)(ii)(C) that rated storage volume equal the mean of the 
measured storage volume of all units within the sample. DOE estimated 
that for electric storage water heaters, the rated storage volume would 
decrease by 10 percent, and for gas-fired and oil-fired water

[[Page 59780]]

heaters, the rated storage volume would decrease by 5 percent.
    6. For each product class and draw pattern, using a simple 
regression, find the slope and intercept where the independent variable 
is the range of adjusted rated storage volumes (determined in step 5) 
and the dependent variable is the UEF values associated with the rated 
storage volumes and specific draw pattern calculated in step 4.
    As discussed in section III.B, the energy conservation standards 
for water heaters established in EPCA (and for electric water heaters, 
the standards as adjusted by the 1990 test procedure final rule) apply 
to all consumer water heaters regardless of storage volume or input 
rate. Therefore, in addition to the classes of water heaters for which 
DOE proposed UEF-based standards in the NOPR, DOE is also proposing 
updated standards based on the UEF test procedure for the types of 
water heaters described in Table III.1.\18\ Although there were few or 
no water heaters in those categories described in Table III.I, DOE used 
the ``representative model'' method described previously by estimating 
values for input rate and recovery efficiency to determine the 
converted UEF standard level.
---------------------------------------------------------------------------

    \18\ These water heaters include gas-fired storage, electric 
storage, and tabletop water heaters at or above 2 gallons storage 
volume and below 20 gallons storage volume; gas-fired storage water 
heaters above 100 gallons storage volume; oil-fired storage water 
heaters above 50 gallons storage volume; electric storage water 
heaters above 120 gallons storage volume; gas-fired instantaneous 
water heaters with an input at or below 50,000 Btu/h or at or above 
2 gallons storage volume; electric instantaneous water heaters at or 
above 2 gallons storage volume; and oil-fired electric instantaneous 
water heaters.
---------------------------------------------------------------------------

    For consumer gas-fired storage water heaters, there are three 
separate conversion factors: (1) For standard (i.e., not low 
NOX or ultra-low NOX) and low NOX non-
condensing models; (2) for ultra-low NOX non-condensing 
models; and (3) for condensing models. For water heaters with a storage 
volume less than or equal to 55 gallons, the conversion factor for 
standard and low NOX non-condensing models was used to 
develop the proposed updated energy conservation standard, as the 
standard for gas-fired storage water heaters with a storage volume less 
than or equal to 55 gallons is at a non-condensing level. DOE chose to 
use the equation for standard and low NOX non-condensing 
models, rather than for ultra-low NOX non-condensing models, 
since standard and low NOX non-condensing models make up the 
majority of the gas-fired storage water heater market. DOE considered 
proposing to establish separate standards for ultra-low NOX 
models based on the conversion factor for these products, but found 
that the slight differences in the resultant standards for ultra-low-
NOX water heaters would not justify the additional 
complexity in the Department's water heater regulations if separate 
standards were to be developed. The average difference between the 
standard and low-NOX and ultra-low-NOX energy 
conservation standards for the very small, low, medium, and high draw 
patterns, was -0.041, -0.008, -0.006, and 0.003, respectively.\19\ 
Manufacturers are required to certify UEF values rounded to the nearest 
0.01 (10 CFR 429.17(b)(2)), so differences lower than that would 
effectively result in the same standard level for the majority of units 
on the market. The very small draw pattern standard would not be 
expected to have a negligible difference; however, DOE is not aware of 
any units that are on the market which would test to this draw pattern. 
DOE did not consider using the condensing gas-fired storage conversion 
for units less than or equal to 55 gallons because the resulting 
standard would be much more stringent than the current energy 
conservation standards. DOE seeks comments on the use of the standard 
and low-NOX conversion to calculate the energy conservation 
standard for consumer gas-fired storage water heaters less than or 
equal to 55 gallons, and its tentative decision not to propose separate 
standards for ultra-low NOX gas-fired storage water heaters. 
This is identified as issue 2 in section V.B, ``Issues on Which DOE 
Seeks Comment.''
---------------------------------------------------------------------------

    \19\ Averages differences are calculated using storage volumes 
from 20 to 55 gallons, in increments of 1 gallon, where the minimum 
UEF values have been rounded to the nearest 0.01.
---------------------------------------------------------------------------

    For consumer gas-fired storage water heaters above 55 gallons, 
there are no water heaters on the market; therefore, DOE assumed the 
input rate to be 65 kBtu/h and the recovery efficiency to be 0.90 when 
performing the conversion to UEF for translating the standard. The 
input rate of 65 kBtu/h was determined based on listings available in 
the AHRI Directory at the time of this analysis. DOE examined all 
models listed in the AHRI Directory (including those marked as 
discontinued or obsolete) and determined that the median input rate of 
gas-fired storage water heaters above 55 gallons is 65 kBtu/h, which is 
also the most frequently occurring input rate. DOE used 0.90 as the 
recovery efficiency based on the recovery efficiency of the only two 
condensing consumer water heater models that DOE has identified on the 
market (both of which have storage volume below 55 gallons). DOE used 
these values along with the conversion factor for condensing gas-fired 
storage water heaters to derive the above 55-gallon energy conservation 
standard. DOE seeks comments from stakeholders regarding its 
assumptions for the typical input rating and recovery efficiency of 
consumer gas-fired storage water heaters above 55 gallons. This is 
identified as issue 3 in section V.B, ``Issues on Which DOE Seeks 
Comment.''
    In the consumer electric instantaneous water heaters product class, 
there are no minimally-compliant models available on the market. 
Therefore, DOE estimated the recovery efficiency for minimally 
compliant models in order to perform the calculations required to 
convert the standard. The recovery efficiency of models available on 
the market is 0.98, while the average EF available on the market was 
0.99. Given the similarity of the EF rating and recovery efficiency 
observed in electric instantaneous models, DOE estimated the recovery 
efficiency of minimally-compliant models as being equal to the EF 
(which at the minimally-compliant level is 0.93). DOE recognizes, 
however, that it is unlikely that a model using electric resistance 
elements would have a recovery efficiency of 0.93, but rather, it is 
more likely that the recovery efficiency of a minimally compliant model 
would be maintained at 0.98 while additional standby losses or cycling 
losses would result in a lower EF. Given the design of products 
currently on the market (upon which the conversion factor is based), 
both cycling and standby losses are minimal, and as a result, the 
conversion factor is based almost entirely on recovery efficiency. 
Therefore, DOE approximated a reduction in cycling and standby losses 
by lowering recovery efficiency such that the overall converted UEF 
would be lowered, in order to keep the converted standard at an 
equivalent level; without this reduction, the resulting standard level 
would be set much closer to the level of performance of current models, 
which would represent an increase in stringency. DOE seeks comment on 
this approach for estimating the recovery efficiency of a minimally-
compliant (i.e., 0.93 EF) electric instantaneous water heater. This is 
identified as issue 4 in section V.B, ``Issues on Which DOE Seeks 
Comment.'' The current DOE-prescribed energy conservation standard for 
electric instantaneous water heaters at 10 CFR 430.32(d) is at the same 
level

[[Page 59781]]

as those set forth in EPCA (42 U.S.C. 6295(e)(1)(C)) and shown in Table 
I.1. These standards are not limited by storage volume, and, therefore, 
DOE has tentatively decided to propose one set of standard equations 
for all storage volumes of consumer electric instantaneous water 
heaters (0 to 10.24 gallons).\20\ To derive the updated energy 
conservation standards for consumer electric instantaneous water 
heaters below 2 gallons, the instantaneous conversion was used, and for 
units at or above 2 gallons, the storage conversion was used. DOE 
believes the use of the storage conversion factor for representative 
units at or above 2 gallons is more appropriate given the greater 
standby losses which would occur during the tests of these units. DOE 
notes that the instantaneous conversion estimates cycling losses for 
instantaneous water heaters and that the storage conversion estimates 
standby losses. Average input rates for units on the market were used 
for below 2 gallons units, and an input rate of 12 kW was assumed for 
all at or above 2 gallons units.
---------------------------------------------------------------------------

    \20\ 10.24 gallons is the maximum possible storage volume for an 
electric instantaneous water heater because EPCA defines these 
products as having no more than one gallon of water per 4,000 Btu 
per hour of input and a maximum input rating of 12 kW. 12 kW 
converts to 40,946 Btu/h, which when divided by 4,000 Btu/h results 
in a maximum storage volume of 10.24 gallons to be considered as an 
electric instantaneous water heater.
---------------------------------------------------------------------------

    For grid-enabled storage water heaters, there were no minimally-
compliant models available on the market at the time of analysis, so 
DOE assumed representative volumes of 75 and 120 gallons and input 
rates of 4.5 kW at both volumes.
    For consumer electric storage water heaters below 20 gallons, DOE 
found that there were units on the market, but these units were not 
reported in the AHRI or CCMS databases. DOE searched through 
manufacturers' product literature to compile a list of units with their 
respective storage volumes and input rates. At each rated storage 
volume, the associated input rates were averaged to obtain a 
representative value. For consumer electric storage water heaters above 
120 gallons, DOE found that there were no units on the market. 
Therefore, DOE assumed representative rated storage volumes of 121 
gallons and 705 gallons. The upper bound of 705 gallons is the point at 
which the applicable EPCA standard, found in Table I.1, would be zero. 
The recovery efficiency is assumed to be 98 percent for all water 
heaters using submerged electric resistance heating elements, and the 
input rate for units with a capacity above 120 gallons is assumed to be 
12 kW (i.e., the maximum allowable input capacity in the consumer 
electric water heater class).
    For consumer tabletop water heaters with storage volumes below 20 
gallons or above 120 gallons, the current DOE-prescribed energy 
conservation standards are at the same level as those prescribed in the 
EPCA standards, found in Table I.1. Therefore, DOE tentatively proposes 
to extend the updated energy conservation standards derived for units 
between 20 and 120 gallons to all tabletop units, regardless of storage 
volume.
    For consumer gas-fired storage water heaters, less than 20 gallons 
and greater than 100 gallons, DOE found that there were no units 
currently on the market. Therefore, DOE assumed that if such models 
were to exist in the less than 20 gallon size, they would have a 
similar representative storage volume as for consumer electric storage 
water heaters less than 20 gallons, and used those values as 
representative storage volumes. For storage volumes above 100 gallons, 
DOE used representative storage volumes of 101 and 326 gallons which 
represent the lower and upper bounds, respectively. The upper bound of 
326 gallons is the point at which the applicable EPCA standard, found 
in Table I.1, would be zero, and DOE used this as the upper bound for 
storage capacity. The recovery efficiency for all units is assumed to 
be the average of the recovery efficiencies available for minimally 
compliant units between 20 and 55 gallons, which was found to be 79 
percent. DOE observed in the AHRI and CCMS databases that there was one 
consumer gas-fired storage water heater at 20 gallons, which had an 
input rate of 75,000 Btu/h. This suggests that the design of consumer 
gas-fired storage water heaters below 20 gallons would trend towards 
higher input rates. Therefore, DOE assumed input rates for units below 
20 gallons to be at the 4,000 Btu/h/gal limitation between storage and 
instantaneous water heaters, which is the maximum input allowable to be 
within the gas-fired storage water heater product class for a given 
volume. (42 U.S.C. 6291(27)(B)) An input rate of 75,000 Btu/h was used 
for storage volumes where the input rate using the 4,000 Btu/h/gal 
limitation would result in a value greater than 75,000 Btu/h, as that 
is the maximum input capacity for consumer gas-fired storage water 
heaters. For consumer gas-fired storage water heaters with greater than 
100 gallons storage volume, the input rate was assumed to be 75,000 
Btu/h.
    For consumer oil-fired storage water heaters with a capacity above 
50 gallons, recovery efficiency and input rate values are assumed to be 
85 percent and 105,000 Btu/h, respectively.
    For consumer oil-fired instantaneous water heaters, the maximum 
possible input rate as defined by EPCA at 42 U.S.C. 6291(27)(B) is 
210,000 Btu/h. This input rate corresponds to a maximum storage volume 
of 52.5 gallons (based on the 4,000 Btu/h per gallon of stored water 
limitation between instantaneous and storage water heaters). Due to the 
large storage volumes that are possible in this class of water heater, 
the consumer oil-fired storage conversion was used to derive the 
updated UEF standards. The average storage volume, input rate, and 
recovery efficiency for units on the market is 5 gallons, 148,000 Btu/
h, and 88 percent, respectively. Therefore, DOE used the representative 
market average data point along with the largest possible storage 
volume and input rate to determine the energy conservation standards 
equation in terms of UEF. A recovery efficiency of 88 percent was also 
used for the 52.5 gallon data point.
    For consumer gas-fired instantaneous water heaters the current DOE-
prescribed energy conservation standards (as amended in the April 2010 
final rule and with which compliance was required in April 2015) cover 
models with: (1) Storage volumes below 2 gallons or (2) an input rate 
above 50,000 Btu/h. All other consumer gas-fired instantaneous water 
heaters would be subject to the standards initially established by EPCA 
shown in Table I.1. These two attributes are not mutually exclusive; 
that is, a unit could exist that has a rated storage volume at or above 
2 gallons and an input rate at or below 50,000 Btu/h. DOE considered 
proposing a separate set of standards for each unique storage volume 
and input rate combination (e.g., above 50,000 Btu/h and at or above 2 
gallons, at or below 50,000 Btu/h and below 2 gallons, or at or below 
50,000 Btu/h and at or above 2 gallons), or proposing a single standard 
that would cover all consumer gas-fired instantaneous water heaters 
with storage volume at or above 2 gallons, or input rate at or below 
50,000 Btu/h. Over the range of applicable storage volumes, the methods 
produce UEF values that are within 0.01 of each other. Therefore, to 
reduce the complexity of its standards for water heaters, DOE proposes 
to use a single set of standard equations for consumer gas-fired 
instantaneous water heaters with rated storage volumes at or above 2 
gallons or input rates at or below 50,000 Btu/h. Representative storage 
volumes of 0, 2, 12.5, and 50 gallons were used to derive the updated 
standards. These

[[Page 59782]]

storage volumes represent various key points. The storage volumes 0 
gallons and 12.5 gallons represent the bounds of instantaneous water 
heaters with an input rate at or below 50,000 Btu/h. (Because an 
instantaneous water heater is defined as containing no more than 1 
gallon of stored water per 4,000 Btu/h of input, the maximum storage 
volume for a 50,000 Btu/h instantaneous water heater is 12.5 gallons.) 
The storage volumes 2 and 50 gallons represent the bounds of 
instantaneous water heaters with storage volumes at or above 2 gallons. 
(Consumer instantaneous water heaters have a maximum input rate of 
200,000 Btu/h. Because instantaneous water heaters are defined as 
having no more than 1 gallon of stored water per 4,000 Btu/h of input, 
the maximum storage volume for a 200,000 Btu/h consumer instantaneous 
water heater is 50 gallons.) DOE assumed that for models at or below 
50,000, Btu/h the representative input rate would be 50,000 Btu/h. For 
the models with a storage volume at 2 gallons, DOE used the input rate 
at the average of models currently available on the market for 
minimally compliant units with 0 gallons of storage volume as the 
representative input rate. DOE assumed that the input rate of such a 
unit would be similar to models on the market with no storage volume. 
For models with a storage volume larger than 2 gallons, DOE assumed a 
representative input rate of 200,000 Btu/h. Recovery efficiencies were 
assumed to be 76 percent for all volumes. This recovery efficiency 
value is less than the average currently available on the market, but 
DOE believes it is more representative of a unit that would have been 
on the market when the EPCA standards were first prescribed. DOE used 
the consumer gas-fired storage conversion to derive the updated 
standards due to the storage volumes being in the range typically 
observed for storage water heaters.
    For residential-duty commercial oil-fired storage water heaters, 
the standard increased from 78 to 80 percent in October 2015. 10 CFR 
431.110. DOE used the average input rates for all residential-duty 
commercial oil-fired storage water heaters that comply with the amended 
standard to derive the inputs needed for the updated energy 
conservation standard.
    For residential-duty commercial electric instantaneous water 
heaters, there were no minimally-compliant units (i.e., thermal 
efficiency of 80 percent) on the market. As with consumer electric 
instantaneous water heaters, DOE recognizes that it is unlikely that a 
model using electric resistance elements would have a thermal 
efficiency of 80 percent, and the thermal efficiency of such equipment 
is likely to be much higher. However, DOE used the thermal efficiency 
value of 80 percent in calculating the equivalent UEF standard, because 
this represents a hypothetical minimally-compliant model. DOE used the 
proposed conversion equation for each draw pattern (see section 
III.E.2.d) to predict the UEF of a minimally-compliant model.
    In response to the translated standards presented in the April 2015 
NOPR, AHRI, Bradford White, and Rheem raised concerns that the 
stringency of the updated standards was not maintained. (AHRI, No. 13 
at p. 4; Bradford White, No. 14 at p. 2; Rheem, No. 11 at p. 2) In 
particular, Rheem commented that 20 of the 43 consumer storage water 
heaters that DOE tested in support of the NOPR generated tested UEF 
values less than the applicable converted UEF value chosen by the DOE 
in the NOPR. Rheem elaborated that, in order for the stringency of 
energy efficiency standards to not be altered during the transition 
from the UEF conversion factor period to the UEF tested value period 
thereafter, a tested value of UEF for a water heater model should 
comply if its converted UEF value complies with the proposed minimum 
standard. (Rheem, No. 11 at p. 5) Rheem also stated that three of the 
seven residential-duty commercial water heaters tested by DOE have 
tested UEF values below their respective analytical-regression UEF 
values. Given that these water heaters currently comply with thermal 
efficiency and standby loss standards in effect and the DOE's tentative 
determination in the NOPR to use the analytical-regression method to 
generate the UEF conversion factor for residential-duty commercial 
water heaters, Rheem asserted that there is cause for concern that the 
UEF conversion factor will result in the minimum energy conservation 
standard for this water heater classification becoming more stringent. 
(Rheem, No. 11 at p. 5)
    Bradford White asserted that the proposed converted standard in 
terms of UEF for electric storage water heaters is more stringent than 
the EF standard. (Bradford White, No. 14 at p. 2) AHRI also claimed 
that the proposed UEF standard for electric storage water heaters is 
too stringent, arguing that the converted UEF values for these models 
in the NOPR were higher than the tested UEF values and that models 
complying with the EF standards would not meet the UEF standards. 
(AHRI, No. 6 at p. 2) Rheem asserted that for consumer electric storage 
water heaters tested using the low draw pattern, test data consistently 
revealed tested UEF values three to four points below the proposed UEF 
minimum. For consumer electric storage water heaters tested using the 
medium draw pattern, Rheem observed that there were some measured UEF 
values two to three points below the proposed UEF minimum. (Rheem, No. 
11 at p. 4) EEI stated that the proposed UEF minimums for electric 
storage water heaters are not neutral for products representing a large 
share of the consumer market. (EEI, No. 17 at p. 2)
    Bradford White stated that the proposed converted standard in terms 
of UEF for gas-fired storage water heaters tested using the high draw 
pattern is less stringent than the EF standard, and that the standard 
for models tested using the medium draw pattern would be more or less 
stringent, depending on the model. (Bradford White, No. 14 at p. 2) 
Rheem stated that for gas-fired storage models tested using the high 
draw pattern, its test data showed measured UEF values two to three 
points higher than the proposed converted UEF standards. EEI commented 
that there were issues with gas-fired storage water heaters at high 
draw patterns, where the converted minimum UEF standard is less 
stringent than the EF standard. (EEI, No. 17 at p. 2)
    Rheem commented that for several models tested by DOE (identified 
in the April 2015 NOPR as CS-6, CS-13, CS-29, CS-30, and CS-39) the 
measured UEF was less than the converted UEF standard. Rheem stated 
that for gas-fired instantaneous water heaters that would be tested 
with the medium draw pattern, the measured UEF is 1 point lower than 
the proposed minimum UEF level. Rheem also stated that for gas-fired 
instantaneous water heaters that would be tested with the high draw 
pattern, the measured UEF is consistently 2 to 3 points higher than the 
proposed minimum UEF level. (Rheem, No. 11 at p. 4) Further, Rheem 
stated that after the 1 year application period of the conversion 
factor, units which previously passed the minimum EF standards could 
test to fail the updated minimum UEF standards. (Rheem, No. 11 at p. 3)
    In response to these comments, DOE acknowledges that the test data 
presented in section III.E.2 show that some units which previously 
passed the EF energy conservation standards would fail the proposed UEF 
standards, while other units which previously failed would now pass. As 
discussed in section III.A, DOE recognizes that the conversion factors 
presented cannot perfectly model the behavior of all water

[[Page 59783]]

heaters, and therefore, uncertainty is carried through to deriving the 
updated energy conservation standards. The standards presented in Table 
III.40 and Table III.41 were derived using a method that was intended 
to reduce the number of units that would either be non-compliant under 
the EF test method and compliant under the UEF test method or vice 
versa, so as to maintain the stringency of the updated standard. 
Nevertheless, to ensure that water heaters which previously passed the 
EF energy conservation standards will continue to comply, pre-existing 
models that are compliant with the EF energy conservation standards are 
``grandfathered,'' as described below in section III.F.
    The proposed standards in terms of uniform energy factor are shown 
below by product class and draw pattern.

                   Table III.40--Proposed Consumer Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
                                       Rated storage volume and
           Product class                   input rating (if            Draw pattern        Uniform energy factor
                                             applicable)
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage Water Heater.....  <20 gal....................  Very Small............  0.2471 - (0.0002 x
                                                                  Low...................   Vr).
                                                                                          0.5132 - (0.0012 x Vr)
                                                                  Medium................  0.5827 - (0.0015 x
                                                                                           Vr).
                                                                  High..................  0.6507 - (0.0019 x
                                                                                           Vr).
                                     >=20 gal and <=55 gal......  Very Small............  0.3456 - (0.0020 x
                                                                                           Vr).
                                                                  Low...................  0.5982 - (0.0019 x
                                                                                           Vr).
                                                                  Medium................  0.6483 - (0.0017 x
                                                                                           Vr).
                                                                  High..................  0.6920 - (0.0013 x
                                                                                           Vr).
                                     >55 gal and <=100 gal......  Very Small............  0.6470 - (0.0006 x
                                                                                           Vr).
                                                                  Low...................  0.7689 - (0.0005 x
                                                                                           Vr).
                                                                  Medium................  0.7897 - (0.0004 x
                                                                                           Vr).
                                                                  High..................  0.8072 - (0.0003 x
                                                                                           Vr).
                                     >100 gal...................  Very Small............  0.1755 - (0.0006 x
                                                                                           Vr).
                                                                  Low...................  0.4671 - (0.0015 x
                                                                                           Vr).
                                                                  Medium................  0.5719 - (0.0018 x
                                                                                           Vr).
                                                                  High..................  0.6916 - (0.0022 x
                                                                                           Vr).
Oil-fired Storage Water Heater.....  <=50 gal...................  Very Small............  0.1822 - (-0.0001 x
                                                                                           Vr).
                                                                  Low...................  0.5313 - (0.0014 x
                                                                                           Vr).
                                                                  Medium................  0.6316 - (0.0020 x
                                                                                           Vr).
                                                                  High..................  0.7334 - (0.0028 x
                                                                                           Vr).
                                     >50 gal....................  Very Small............  0.1068 - (0.0007 x
                                                                                           Vr).
                                                                  Low...................  0.4190 - (0.0017 x
                                                                                           Vr).
                                                                  Medium................  0.5255 - (0.0021 x
                                                                                           Vr).
                                                                  High..................  0.6438 - (0.0025 x
                                                                                           Vr).
Electric Storage Water Heaters.....  <20 gal....................  Very Small............  0.7836 - (0.0013 x
                                                                                           Vr).
                                                                  Low...................  0.8939 - (0.0008 x
                                                                                           Vr).
                                                                  Medium................  0.9112 - (0.0007 x
                                                                                           Vr).
                                                                  High..................  0.9255 - (0.0006 x
                                                                                           Vr).
                                     >=20 gal and <=55 gal......  Very Small............  0.8808 - (0.0008 x
                                                                                           Vr).
                                                                  Low...................  0.9254 - (0.0003 x
                                                                                           Vr).
                                                                  Medium................  0.9307 - (0.0002 x
                                                                                           Vr).
                                                                  High..................  0.9349 - (0.0001 x
                                                                                           Vr).
                                     >55 gal and <=120 gal......  Very Small............  1.9236 - (0.0011 x
                                                                                           Vr).
                                                                  Low...................  2.0440 - (0.0011 x
                                                                                           Vr).
                                                                  Medium................  2.1171 - (0.0011 x
                                                                                           Vr).
                                                                  High..................  2.2418 - (0.0011 x
                                                                                           Vr).
                                     >120 gal...................  Very Small............  0.6802 - (0.0003 x
                                                                                           Vr).
                                                                  Low...................  0.8620 - (0.0006 x
                                                                                           Vr).
                                                                  Medium................  0.9042 - (0.0007 x
                                                                                           Vr).
                                                                  High..................  0.9437 - (0.0007 x
                                                                                           Vr).
Tabletop Water Heater..............  All........................  Very Small............  0.6323 - (0.0058 x
                                                                                           Vr).
                                                                  Low...................  0.9188 - (0.0031 x
                                                                                           Vr).
                                                                  Medium................  0.9577 - (0.0023 x
                                                                                           Vr).
                                                                  High..................  0.9884 - (0.0016 x
                                                                                           Vr).
Instantaneous Gas-fired Water        <2 gal and >50,000 Btu/h...  Very Small............  0.7964 - (0.0000 x
 Heater.                                                                                   Vr).
                                                                  Low...................  0.8055 - (0.0000 x
                                                                                           Vr).
                                                                  Medium................  0.8070 - (0.0000 x
                                                                                           Vr).
                                                                  High..................  0.8086 - (0.0000 x
                                                                                           Vr).
                                     >=2 gal or <=50,000 Btu/h..  Very Small............  0.3013 - (0.0023 x
                                                                                           Vr).
                                                                  Low...................  0.5421 - (0.0024 x
                                                                                           Vr).
                                                                  Medium................  0.5942 - (0.0021 x
                                                                                           Vr).
                                                                  High..................  0.6415 - (0.0017 x
                                                                                           Vr).
Instantaneous Oil-fired Water        All........................  Very Small............  0.1430 - (0.0015 x
 Heater.                                                                                   Vr).
                                                                  Low...................  0.4455 - (0.0023 x
                                                                                           Vr).
                                                                  Medium................  0.5339 - (0.0023 x
                                                                                           Vr).
                                                                  High..................  0.6245 - (0.0021 x
                                                                                           Vr).
Instantaneous Electric Water Heater  All........................  Very Small............  0.9161 - (0.0039 x
                                                                                           Vr).
                                                                  Low...................  0.9159 - (0.0009 x
                                                                                           Vr).
                                                                  Medium................  0.9160 - (0.0005 x
                                                                                           Vr).
                                                                  High..................  0.9161 - (0.0003 x
                                                                                           Vr).
Grid-Enabled Water Heater..........  >75 gal....................  Very Small............  1.0136 - (0.0028 x
                                                                                           Vr).

[[Page 59784]]

 
                                                                  Low...................  0.9984 - (0.0014 x
                                                                                           Vr).
                                                                  Medium................  0.9853 - (0.0010 x
                                                                                           Vr).
                                                                  High..................  0.9720 - (0.0007 x
                                                                                           Vr).
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.


          Table III.41--Proposed Residential-Duty Commercial Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
                    Product class                              Draw pattern             Uniform energy factor
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage....................................  Very Small..................  0.2670 - (0.0009 x Vr).
                                                       Low.........................  0.5356 - (0.0012 x Vr).
                                                       Medium......................  0.5996 - (0.0011 x Vr).
                                                       High........................  0.6592 - (0.0009 x Vr).
Oil-fired Storage....................................  Very Small..................  0.2932 - (0.0015 x Vr).
                                                       Low.........................  0.5596 - (0.0018 x Vr).
                                                       Medium......................  0.6194 - (0.0016 x Vr).
                                                       High........................  0.6740 - (0.0013 x Vr).
Electric Instantaneous...............................  Very Small..................  0.80
                                                       Low.........................  0.80
                                                       Medium......................  0.80
                                                       High........................  0.80
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.

    Lutz suggested determining the energy conservation standards using 
only test data from minimally-compliant water heaters. He stated that 
this method would remove the uncertainty which compounds throughout the 
conversion process. (Lutz, No. 16 at p. 3) DOE believes that an 
appropriate amount of minimally-compliant water heater test data is 
currently not present to pursue this method. Based on stakeholder 
comments, DOE selected units for testing with a range of attributes and 
associated EF levels. As the effect of the uniform efficiency 
descriptor test procedure cannot be fully known without testing all 
units on the market, it is a possibility that a minimally compliant 
unit may perform better than a unit that was rated above the minimum. 
Further, a water heater would have to have a tested EF at the minimum 
energy conservation standard, not just be rated at the minimum. 
Therefore, for these reasons, DOE did not use this method for deriving 
the proposed standards.
    Rheem and AHRI argued that the relative difference between the 
minimum EF and EF should be maintained between the minimum UEF and UEF 
values. (Rheem, No. 11 at p. 3; AHRI, No. 6 at p. 2) AHRI also asserted 
that if the relative difference is not maintained, then a 
manufacturer's investment could be wasted. (AHRI, No. 3 at p. 2) AHRI 
expressed the view that it is more important to look at the difference 
in the measurements between the EF and UEF test procedures, and 
recommended that DOE should examine the difference in EF and UEF 
measurements for models rated at the applicable minimum EF value to 
help check the validity of the proposed converted minimum standards. 
(AHRI, No. 13 at p. 5) DOE agrees that the relative difference between 
minimum and rated values is an important factor to consider when 
developing the energy conservation standards. The proposed 
``representative model'' method uses the EF-denominated energy 
conservation standard values to derive the new standard equations; 
therefore, DOE believes the stringency of the standards is maintained 
for the market as a whole. However, test data show that water heaters 
do not all have the same reaction to the new test procedure, and as 
such, the relative difference in the standards cannot be exactly 
maintained for each individual model. In addition, not all 
manufacturers rate models with the same degree of conservativism, so 
the relationship between rated and measured values is not constant.
    Regarding specifically the energy conservation standards for the 
residential-duty commercial water heater equipment class, EEI stated 
that this was a non-standard process for creating the proposed 
standards. (EEI, No. 5 at p. 2) In response, DOE clarifies that DOE is 
not creating new standards for residential-duty commercial water 
heaters. Rather, this equipment has always been covered under the 
applicable commercial water heating equipment standards. DOE is simply 
translating the commercial water heating equipment standards from the 
thermal efficiency and standby loss metrics in use today to the UEF 
metric for the subset of commercial water heating equipment that would 
meet the definition of a ``residential-duty commercial water heater'' 
at 10 CFR 431.102.
a. Storage Volume Used for Calculations
    In the July 2014 final rule, DOE amended the certification 
requirements for consumer water heaters to specify that the rated 
storage volume of a water heater is the mean of the measured storage 
volume. 79 FR 40542, 40565 (July 11, 2014). Commenters requested 
clarification on how the rated storage volume will be applied in this 
rulemaking. (AHRI, No. 3 at p. 2; A. O. Smith, No. 13 at p. 2; Bradford 
White, No. 14 at p. 3; NEEA, No. 15 at p. 7; Rheem, No. 11 at p. 8)
    As discussed in the preceding section, DOE has accounted for the 
amended certification requirements with regard to the rated storage 
volume in this rulemaking when translating the standards. First, DOE 
used the rated storage volumes prior to the effective date of the 
requirement that the rated storage volume of a water heater be the mean 
of the measured storage volume to calculate the EF-denominated 
standards with which to maintain equivalency for each model. Therefore, 
the stringency of the EF-denominated standards that DOE converted did 
not change due to the new certification requirements. Second, when 
calculating the converted UEF standards equations, DOE adjusted the 
rated storage volume to reflect its new

[[Page 59785]]

requirement that the rated storage volume be equal to the mean of the 
measured volume of units in the certification sample (since the storage 
volumes initially examined were certified prior to the effective date 
of this requirement).
    Before DOE instituted this requirement, a manufacturer had some 
freedom to choose a volume rating, subject to industry safety standards 
under which a rated volume had to be within 5 percent of the actual 
volume for a fossil-fuel-fired water heater or within 10 percent for an 
electric water heater. Meanwhile, the operation of DOE's energy 
conservation standard for water heaters gave manufacturers an incentive 
to rate the volumes of their products as high as possible--because the 
applicable standard decreased for larger volumes. The combined effect 
of these two influences, DOE believes, is that fossil-fuel-fired water 
heaters ordinarily had volume ratings 5 percent higher than their 
actual volumes, and electric water heaters 10 percent higher. DOE's 
observations on actual products is consistent with that conclusion.
    Consequently, DOE estimated the measured volume as 0.95 times 
(i.e., 5 percent lower than) the rated storage volume for fossil fuel 
fired water heaters and 0.90 times (i.e., 10 percent lower than) the 
rated storage volume for electric water heaters. By adjusting the 
storage volume to reflect what will be the new rated storage volumes 
that are 5 percent or 10 percent (for fossil fuel and electric water 
heaters, respectively) below the previous rated storage volume, DOE has 
accounted for the change in its regulations regarding the rating of 
storage volumes, and the UEF standard equation will represent the 
relationship between the new rated storage volume (equivalent to the 
mean of the measured storage volume for test samples) and UEF. Figure 
III.1 below shows an example representation of how the energy 
conservation standards are related to each other based on the rated or 
estimated measured storage volumes.
BILLING CODE 6450-01-C
[GRAPHIC] [TIFF OMITTED] TP30AU16.038

BILLING CODE 6150-01-P
    In the July 2014 test procedure final rule, DOE added enforcement 
provisions that state that the rated value for storage volume during 
enforcement testing will be considered valid only if the measurement is 
within 5 percent of the certified rating. If the rated storage volume 
is within 5 percent of the mean of the measured value of storage 
volume, then that value will be used as the basis for calculation of 
the required uniform energy factor for the basic model; otherwise, the 
mean of the measured values will be used as the basis for calculation 
of the required

[[Page 59786]]

uniform energy factor for the basic model. 79 FR 40542, 40566 (July 11, 
2014); 10 CFR 429.134(d)(2). DOE reviewed the measured storage volume 
test data for models included in the analysis for this SNOPR and 
observed that for models which were tested more than once, the measured 
storage volume was well within five percent of the mean of the measured 
storage volumes (which will be required to be equal to the rated 
storage volume under 10 CFR 429.17(a)(1)(ii)(C)) for each respective 
model. The data set of models tested more than once consists of 10 
unique models with 24 total storage volume tests (each model was tested 
2 or 3 times). For each model, DOE calculated the mean, standard 
deviation, and 99.7-percent confidence interval (i.e., 3 times the 
standard deviation of the measured storage volumes) of the measured 
storage volumes. DOE then compared the mean of the measured storage 
volume to the 99.7-percent confidence interval to determine the percent 
deviation from the mean value that would be within the 99.7-percent 
confidence interval. The maximum percent change from the mean that 
would be within the 99.7-percent confidence interval was slightly under 
one percent. Therefore, DOE proposes to change its enforcement-specific 
provisions for water heaters to specify that the rated value for 
storage volume during enforcement testing will be considered valid only 
if the measurement is within 2 percent of the certified rating. DOE 
believes two percent more accurately reflects the level of variability 
that manufacturers are currently able to achieve, and allows for 
slightly more variability than what was observed in the sample set of 
this SNOPR.

F. Compliance and Grandfathering

    AHRI, Bradford White, Rheem, and EEI recommended that DOE should 
add provisions to state that any water heater models tested and meeting 
the minimum EF requirements prior to July 13, 2015 (i.e., those meeting 
the standards promulgated in the April 2010 final rule and requiring 
compliance on April 16, 2015), would be considered as meeting the 
minimum UEF requirements. (AHRI, No. 13 at p. 8; Bradford White, No. 14 
at p. 2; Rheem, No. 11 at p. 3; EEI, No. 17 at p. 3) AHRI, Bradford 
White, and EEI stated that the proposed standards are to be neither 
more nor less stringent than the EF-denominated standards, as stated in 
42 U.S.C. 6293(e), and that this implies grandfathering water heater 
models will be included in this rulemaking. (AHRI, No. 13 at p. 8; 
Bradford White, No. 14 at p. 1; EEI, No. 17 at p. 3) Further, Rheem 
argued that at the time of the switch from allowing the converted UEF 
to requiring the tested UEF for demonstrating compliance, a tested UEF 
value should comply if the converted value passes. (Rheem, No. 11 at p. 
5) EEI asserted that compliance or non-compliance with the standard can 
only be determined through the test procedure and that a unit which 
meets the efficiency standard under the old test procedure should be 
valid for sale, regardless of the conversion factor result. (EEI, No. 
17 at p. 3) EEI also argued that the conversion values should only be 
used on the FTC EnergyGuide label. (EEI, No. 17 at p. 3) AHRI stated 
that the converted minimum UEF standards will not have perfect one-to-
one correlation with every currently complying model, and therefore, it 
is essential that DOE establish how grandfathering will be applied so 
that manufacturers can properly assess the validity of the converted 
minimum UEF standards. (AHRI, No. 13 at p. 8)
    In a paragraph titled ``Existing covered water heaters,'' EPCA 
provides that a covered water heater (i.e., a water heater subject to 
the UEF test procedure rule) is considered to comply with the UEF test 
procedure rule on and after the effective date of the final rule (i.e., 
July 13, 2015) and with any revised labeling requirements established 
by the Federal Trade Commission (FTC) to carry out the final rule if 
the covered water heater was manufactured prior to the effective date 
of the final rule; and (ii) complied with the efficiency standards and 
labeling requirements in effect prior to the final rule. (42 U.S.C. 
6295(e)(5)(K)) EPCA defines the ``final rule,'' in this context, to be 
the UEF test procedure final rule. (42 U.S.C. 6295(e)(5)(A)(ii)) The 
natural reading of this provision is that a water heater (a unit \21\) 
manufactured prior to July 13, 2015, and compliant with the pre-
existing standards when tested using the test procedure in effect on 
July 13, 2014, is deemed to comply with the UEF test procedure final 
rule and any corresponding label changes made by the FTC.
---------------------------------------------------------------------------

    \21\ DOE notes that EPCA appears to distinguish in paragraph 
(e)(5) of section 6295 between certain provisions that apply on a 
unit-by-unit basis and other provisions that apply on a model-by-
model basis.
---------------------------------------------------------------------------

    Manufacturers appear to read this provision to provide 
``grandfathering'' with respect to compliance with the converted 
standards. The language does not provide such relief, nor is such 
relief necessary. The standard applicable to a unit is the standard in 
effect at the time of manufacture; therefore, units manufactured prior 
to July 13, 2015, must comply with the corresponding EF/TE/STB 
standards, and no ``grandfathering'' is needed. The relevance of the 
UEF test procedure with respect to such units is for the purposes of 
representations, which this statutory provision explicitly addresses. 
Accordingly, DOE reads 42 U.S.C. 6295(e)(5)(K) to provide that 
manufacturers do not have to retest units of water heaters using the 
UEF test procedure if they were tested and rated prior to July 13, 
2015. DOE notes there is a corresponding provision with respect to the 
FTC label.
    In addition, EPCA provides that manufacturers may use the 
conversion factor in lieu of testing for models tested prior to July 
13, 2015, for a period of one year following the publication of a final 
rule. In this way, EPCA provides additional relief to manufacturers for 
models of water heaters that continue to be manufactured on or after 
July 13, 2015, by delaying the need to complete testing using the UEF 
test procedure for those models of water heaters manufactured prior to 
July 13, 2015. See 42 U.S.C. 6295(e)(5)(E) (indicating the conversion 
factor applies to ``models of covered water heaters'' (emphasis 
added)); compare 42 U.S.C. 6295(e)(5)(K) (referring to ``existing 
covered water heaters'' and ``a covered water heater'' rather than a 
``model of covered water heater'').
    DOE recognizes that the nature of this conversion process could 
conceivably result in a few models very close to the standard falling 
below the converted standard. Although the statute does not provide 
``grandfathering'' of the sort envisioned by manufacturers, DOE 
believes that there is value in reducing the uncertainty for 
manufacturers and that there is no significant public harm in letting 
manufacturers continue sales of certain models. As discussed in great 
detail throughout this notice, every model responds slightly 
differently to the change in the test procedure. As a result, there is 
variability, and units very near the standard level (either above or 
below) could have a measured efficiency using the new test procedure 
that would change the compliance status of that unit. Accordingly, DOE 
will determine the compliance of a basic model--the level of 
granularity typically used by DOE and manufacturers to evaluate 
compliance--using the test procedure in effect prior to July 13, 2015, 
under the following circumstance: The basic model must have been in 
distribution in commerce prior to July 13, 2015; the basic model must 
have been tested and properly certified to

[[Page 59787]]

DOE as compliant with the applicable standard prior to July 13, 2015; 
and the units manufactured prior to July 13, 2015, must be essentially 
identical to the units manufactured on or after July 13, 2015. The last 
requirement for this policy--that units must be essentially identical--
bears explanation. DOE generally permits manufacturers great latitude 
in assigning basic model numbers, and manufacturers normally are not 
required to certify a model as a new basic model if modifications make 
the model more efficient. In implementing this policy, DOE believes 
that, if a manufacturer makes changes to a model (that make it either 
more efficient or less), then it should conduct the requisite testing 
using the UEF test procedure and ensure the compliance of the model 
with the converted standard. This policy is intended to give certainty 
to manufacturers with respect to historical models; it is not intended 
to provide a mechanism to perpetuate an obsolete test method and 
obsolete metrics.
    In summary, EPCA provides that units of water heaters can continue 
to have their efficiency represented in terms of the ``old'' metrics. 
EPCA also provides that manufacturers can use the conversion factors to 
determine represented values for a period of one year following 
issuance of a final rule in this rulemaking for models that were being 
manufactured prior to July 13, 2015. Under EPCA, units manufactured on 
or after July 13, 2015, must meet the standard as denominated in the 
UEF metric; however, DOE will implement an enforcement policy that DOE 
will not seek civil penalties for the continued manufacture and 
distribution in commerce of units of certain basic models as follows: 
The basic model must have been in distribution in commerce prior to 
July 13, 2015; the basic model must have been tested and properly 
certified to DOE as compliant with the applicable standard prior to 
July 13, 2015; and the units manufactured prior to July 13, 2015, must 
be essentially identical to the units manufactured on or after July 13, 
2015.
    DOE recognizes that manufacturers seek certainty that models 
introduced since July 13, 2015, will not be subject to civil penalties. 
In enforcing the standard(s), DOE will consider whether these models 
meet the standard(s) as denoted using the ``old'' metric(s), the 
deviation from the UEF standard when tested using the UEF test 
procedure, and efforts taken by the manufacturer to ensure compliance 
with the converted, UEF standards. DOE does not intend to issue a 
``grandfathering'' enforcement policy with respect to basic models 
introduced on and after July 13, 2015, as such a policy does not appear 
to be necessary at this time.

G. Certification

    EPCA requires that the standard for covered water heaters be in 
terms of UEF as of July 13, 2015. Accordingly, in the April 2015 NOPR, 
DOE proposed to require manufacturers to provide EF and UEF for 
consumer water heaters (or thermal efficiency and standby loss and UEF 
for residential-duty commercial water heaters) in certification reports 
filed between July 13, 2015, and the compliance date determined by the 
final rule in this rulemaking. 80 FR 20116, 20138 (April 14, 2015). DOE 
proposed that manufacturers would not be required to submit revised 
certification reports for previously certified basic models until the 
next annual certification date (May 1). Id.
    In the April 2015 NOPR, DOE noted that allowing manufacturers to 
submit both EF and UEF data would allow manufacturers to fulfill the 
statutory requirement to begin using UEF for purposes of compliance 
with standards but would also allow manufacturers to provide the 
necessary information to determine costs under the current FTC labeling 
requirements. DOE stated that this would also allow a transition period 
for FTC to pursue a rulemaking to determine whether changes are needed 
to the water heater EnergyGuide label due to changes in the water 
heater test procedure. Lastly, DOE stated that it expects that the 
conversion factors proposed in this notice could be used to convert EF 
to UEF for previously certified basic models or to convert UEF values 
``backwards'' to EF to determine the appropriate costs for labeling of 
new basic models until FTC has determined whether to make changes to 
the label. Id.
    In his comments, Lutz requested that standby heat loss coefficient 
(UA), Annual Energy Consumption (Eannual), Annual Electrical 
Energy Consumption (Eannual,e), and Annual Fossil Fuel 
Energy Consumption (Eannual,f) be included in the parameters 
manufacturers are required to submit to DOE and further that they be 
available to the public in the Compliance Certification Database. Lutz 
stated that these parameters are already calculated during the UEF test 
procedure and would help analysts estimate energy consumption of water 
heaters when operating under conditions that do not exactly match the 
draw patterns or other conditions specified in the laboratory test 
procedure. (Lutz, No. 20 at p. 1) DOE has tentatively decided not to 
add these values as part of the certification report; however, DOE is 
specifically requesting comment from stakeholders about whether these 
performance characteristics should be added in the final rule, either 
as publicly reported characteristics of water heaters or as information 
that is not published on the DOE Web site.
    AHRI, A.O. Smith, and Rheem commented that DOE should delay the 
effective date of the uniform energy descriptor test procedure. (AHRI, 
No. 13 at p. 3; A.O. Smith, No. 10 at pp. 1-2; Rheem, No. 11 at p. 10) 
Specifically, AHRI argued that the statutory timeline cannot override 
the substantive statutory protections that Congress provided, and it is 
imperative that DOE take the time and effort to conduct the testing and 
analysis necessary to ensure that the statutory requirements are met. 
AHRI also stated that to proceed with implementing the UED test 
procedure on July 13, 2015, without the existence of appropriate 
conversion factors, would violate the statute and serve no purpose 
except to further confuse an already complex situation. (AHRI, No. 13 
at pp. 2-3) A.O. Smith urged the postponement of the implementation 
date because new models would be tested to the new test method and have 
a valid UEF rating, but without a valid conversion factor in place to 
convert the relevant minimum efficiency requirement into terms of UEF, 
there is no basis for determining whether the new model is compliant 
with minimum efficiency standards. (A.O. Smith, No. 10 at pp. 1-2) 
Rheem stated that new consumer water heater models introduced in the 
time period between the compliance date of the amended test procedure 
and the conversion of the minimum standards will have to be certified 
with the UEF descriptor in accordance with the UEF test procedure rule, 
but there will be no established minimum UEF standard for that model to 
achieve. Rheem asserted that such uncertainty will prevent the launch 
of new consumer water heater models and cause significant harm to Rheem 
and its customers. Rheem requested a delay in implementation of the 
uniform energy descriptor to permit the necessary changes to product 
and carton labeling and communications that display energy efficiency 
metrics for all manufactured consumer and residential-duty commercial 
water heater units. (Rheem, No. 11 at pp. 9-10). NEEA strongly 
supported the Department's proposal to defer re-certification of 
existing water heater models until May 2016, noting that manufacturers 
would need time to transition to the UEF testing and/or calculation 
regime

[[Page 59788]]

specified as a result of this rulemaking. (NEEA, No. 15 at p. 7)
    Several commenters also cited the complexities of coordinating the 
DOE metric change with the FTC labelling process, and argued that the 
need for coordination with FTC should delay the implementation of the 
uniform efficiency descriptor. A.O. Smith stated the need to coordinate 
FTC labeling rules with the UEF requirements as a reason to delay 
implementation, and elaborated that without a valid set of conversion 
factors, a manufacturer will not be able to ``back calculate'' cost of 
operation for the FTC label from a tested UEF. (A.O. Smith, No. 10 at 
p. 2) GE commented that DOE should harmonize with the FTC labeling 
process, and fully implement the UEF and conversion once the FTC label 
has been modified to account for the different usage patterns in the 
UEF test method. (GE, No. 12 at p. 2) Rheem recommended postponing the 
adoption of reporting requirements until FTC has had an opportunity to 
evaluate the EnergyGuide label and revise its format to reflect the 
metrics derived from the UEF. Rheem noted that the FTC label requires 
information based on the measurement of EF and that a conversion method 
would be needed to calculate the EF based on the UEF. Rheem stated that 
such conversions for marketing and labeling materials will result in 
displays of performance and cost metrics based upon two different 
energy efficiency descriptors, which will confuse consumers. Rheem also 
raised concerns that the differences in energy and water consumption 
based on the delivery capacity in the UEF test method will lead to 
differences in annual operating costs reported on the label, which 
could create an incentive for manufacturers to display the information 
based on UEF for low and medium usage water heaters in order to display 
expected lower operating costs. (Rheem, No. 11 at p. 9) AHRI stated 
that, after the compliance date of the UEF test procedure, DOE will 
require manufacturers to certify UEF values, but for the FTC label, 
manufacturers must also have EF-based information. Although DOE had 
proposed not to require updated certification reports containing 
represented values for UEF until May 1, 2016, AHRI asserted that to 
comply with the information requirements of EPCA under section 6293(c), 
manufacturers must provide the market with UEF-based information. AHRI 
stated that FTC enforces both the EnergyGuide information and general 
manufacturer claims regarding their products under the unfair and 
deceptive trade practices provisions pursuant to section 6303(c), and 
if manufacturers display information not in conformance with Federally-
mandated test procedures, this may be considered a deceptive trade 
practice. (AHRI, No. 13 at p. 2)
    DOE understands the difficulties created by the timing of both the 
uniform efficiency descriptor rulemaking and the present conversion 
factor rulemaking for covered water heaters. However, these rulemakings 
dealt with matters of significant complexity and necessitated a 
substantial amount of testing to ensure the accuracy and validity of 
results, as reflected by requests from industry for extended comment 
periods and additional DOE testing. Consequently, DOE was not able to 
meet the regulatory timeline envisioned by Congress, and as a result, 
the Department seeks to alleviate any hardships raised by the current 
timeline.
    Upon the effective date of the final rule that results from this 
rulemaking, certification of compliance with energy conservation 
standards will be exclusively in terms of UEF. DOE has tentatively 
concluded that there will be three possible paths available to 
manufacturers for certifying compliance of basic models of consumer 
water heaters that were certified before July 13, 2015: (1) In the year 
following the final rule in this rulemaking, convert the energy factor 
values obtained using the test procedure contained in appendix E to 
subpart B of 10 CFR part 430 of the January 1, 2015 edition of the CFR 
from energy factor to uniform energy factor using the applicable 
mathematical conversion factor, and then use the converted uniform 
energy factors along with the applicable sampling provisions in 10 CFR 
part 429 to determine the represented uniform energy factor; or (2) 
Conduct testing using the test procedure contained at appendix E to 
subpart B of 10 CFR part 430, effective July 13, 2015, along with the 
applicable sampling provisions in 10 CFR part 429; or (3) Where 
permitted, apply an alternative efficiency determination method (AEDM) 
pursuant to 10 CFR 429.70 to determine the represented efficiency of 
basic models for those categories of consumer water heaters where the 
``tested basic model'' was tested using the test procedure contained at 
appendix E to subpart B of 10 CFR part 430, effective July 13, 2015.
    Similarly, DOE has tentatively concluded that there will be three 
possible paths available to manufacturers for certifying compliance of 
basic models of commercial residential-duty water heaters that were 
certified before July 13, 2015: (1) In the year following the final 
rule in this rulemaking, convert the thermal efficiency and standby 
loss values obtained using the test procedure contained in 10 CFR 
431.106 of the January 1, 2015 edition of the CFR from thermal 
efficiency and standby loss to uniform energy factor using the 
applicable mathematical conversion factor, and then use the converted 
uniform energy factors along with the applicable sampling provision in 
10 CFR part 429 to determine the represented uniform energy factor; or 
(2) Conduct testing using the test procedure at 10 CFR 431.106, 
effective July 13, 2015, along with the applicable sampling provisions 
in part 429; or (3) Where permitted, apply an alternative efficiency 
determination method (AEDM) pursuant to 10 CFR 429.70 to determine the 
represented efficiency of basic models for those categories of 
commercial water heaters where the ``tested basic model'' was tested 
using the test procedure at 10 CFR 431.106, effective July 13, 2015.
    DOE has already issued an enforcement policy not to seek civil 
penalties for certification violations during the pendency of this 
rulemaking. Under that policy, manufacturers are not held accountable 
for submitting certification reports until a conversion factor final 
rule is published. DOE intends to extend the certification portion of 
that policy for an appropriate time period to allow manufacturers to 
certify compliance using the conversion factors. DOE notes that 
certification of basic models that were certified prior to July 13, 
2015, will only require the application of the appropriate conversion 
formula(s) from the final rule and, thus, should not require a 
significant amount of time to complete certification. As the test 
procedure has been final for more than a year, DOE also expects that 
the time to complete certification for basic models introduced after 
July 13, 2015, will not be significant. DOE welcomes data from industry 
regarding the necessary time to submit such reports.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

    The Office of Management and Budget (OMB) has determined that test 
procedure rulemakings do not constitute ``significant regulatory 
actions'' under section 3(f) of Executive Order 12866, Regulatory 
Planning and Review, 58 FR 51735 (Oct. 4, 1993). Accordingly, this 
action was not subject to review under the Executive Order by the 
Office of Information and Regulatory Affairs

[[Page 59789]]

(OIRA) in the Office of Management and Budget.

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of an initial regulatory flexibility analysis (IFRA) for 
any rule that by law must be proposed for public comment, unless the 
agency certifies that the rule, if promulgated, will not have a 
significant economic impact on a substantial number of small entities. 
As required by Executive Order 13272, ``Proper Consideration of Small 
Entities in Agency Rulemaking,'' 67 FR 53461 (August 16, 2002), DOE 
published procedures and policies on February 19, 2003, to ensure that 
the potential impacts of its rules on small entities are properly 
considered during the DOE rulemaking process. 68 FR 7990. DOE has made 
its procedures and policies available on the Office of the General 
Counsel's Web site: http://energy.gov/gc/office-general-counsel.
    This proposed rule would prescribe a mathematical conversion that 
would be used on a limited basis to determine the represented values 
for consumer water heaters and certain commercial water heaters. For 
consumer water heaters and certain commercial water heaters, the 
mathematical conversion would establish a bridge between the rated 
values based on the results under the energy factor, thermal 
efficiency, and standby loss test procedures (as applicable) and the 
uniform energy factor test procedure. DOE reviewed this proposed rule 
under the provisions of the Regulatory Flexibility Act and the policies 
and procedures published on February 19, 2003. 68 FR 7990.
    For the manufacturers of the covered water heater products, the 
Small Business Administration (SBA) has set a size threshold, which 
defines those entities classified as ``small businesses'' for the 
purposes of the statute. DOE used the SBA's small business size 
standards to determine whether any small entities would be subject to 
the requirements of the rule. 65 FR 30836, 30849 (May 15, 2000), as 
amended at 65 FR 53533, 53545 (Sept. 5, 2000), at 77 FR 49991, 50008-11 
(August 20, 2012), and at 81 FR 4469, 4490 (Jan. 26, 2016), and 
codified at 13 CFR part 121. The size standards are listed by North 
American Industry Classification System (NAICS) code and industry 
description and are available at https://www.sba.gov/sites/default/files/files/Size_Standards_Table.pdf. Consumer water heater 
manufacturing is classified under NAICS code 335228--''Other Major 
Household Appliance Manufacturing.'' The SBA sets a threshold of 1,000 
employees or less for an entity to be considered as a small business. 
Commercial water heater manufacturing is classified under NAICS code 
333318--``Other Commercial and Service Industry Machinery 
Manufacturing,'' for which SBA sets a size threshold of 1,000 employees 
or fewer as being considered a small business.
    DOE has identified 11 manufacturers of consumer water heaters that 
can be considered small businesses. DOE identified five manufacturers 
of ``residential-duty'' commercial water heaters that can be considered 
small businesses. Four of the ``residential-duty'' commercial water 
heater manufacturers also manufacture consumer water heaters, so the 
total number of small water heater manufacturers impacted by this rule 
would be 12. DOE's research involved reviewing several industry trade 
association membership directories (e.g., AHRI), product databases 
(e.g., CCMS, AHRI, CEC, and ENERGY STAR databases), individual company 
Web sites, and marketing research tools (e.g., Hoovers reports) to 
create a list of all domestic small business manufacturers of products 
covered by this rulemaking.
    For the reasons explained below, DOE has concluded that the test 
procedure amendments contained in this proposed rule would not have a 
significant economic impact on any manufacturer, including small 
manufacturers.
    For consumer water heaters that were covered under the energy 
factor test procedure and energy conservation standards, the conversion 
factor in this proposed rule would convert the rated values based on 
the energy factor test procedure to values based on the uniform energy 
factor test procedure. Likewise, for certain commercial water heaters, 
defined under the term ``residential-duty commercial water heater,'' 
the conversion factor in this proposed rule would convert the rated 
values based on the previous test procedure to the uniform descriptor 
which is based on the UEF test procedure. The energy conservation 
standards for commercial water heating equipment will be denominated 
using the uniform descriptor.
    The conversion factor proposal accomplishes two tasks: (1) 
Translating the EF-, TE-, and SL-denominated (as applicable) energy 
conservation standards for consumer water heaters and certain 
commercial water heaters to being expressed in terms of the metric and 
test procedure for uniform energy factor; and (2) providing a limited 
conversion factor that manufacturers can use to translate represented 
values established for basic models certified prior to July 13, 2015. 
This limited conversion is a burden-reducing measure which helps to 
ease the transition of the market to the new test procedure and uniform 
metric over the one-year period instead of the typical 180 day 
timeframe allotted by statute. In addition, as discussed in section 
III.F, DOE will implement an enforcement policy that DOE will not seek 
civil penalties for the continued manufacture and distribution in 
commerce of units of certain basic models that meet certain conditions 
(as described in III.F), thereby further reducing any burden on small 
business manufacturers. Accordingly, DOE concludes and certifies that 
this rule, if finalized, would not have a significant economic impact 
on a substantial number of small entities, so DOE has not prepared a 
regulatory flexibility analysis for this rulemaking. DOE will provide 
its certification and supporting statement of factual basis to the 
Chief Counsel for Advocacy of the SBA for review under 5 U.S.C. 605(b).
C. Review Under the Paperwork Reduction Act of 1995
    Manufacturers of water heaters must certify to DOE that their 
products comply with any applicable energy conservation standards. In 
certifying compliance, manufacturers must test their products according 
to the DOE test procedures for water heaters, including any amendments 
adopted for those test procedures. DOE has established regulations for 
the certification and recordkeeping requirements for all covered 
consumer products and commercial equipment, including consumer and 
commercial water heaters. 76 FR 12422 (March 7, 2011); 79 FR 25486 (May 
5, 2014). The collection-of-information requirement for the 
certification and recordkeeping is subject to review and approval by 
OMB under the Paperwork Reduction Act (PRA). This requirement was 
approved by OMB under OMB control number 1910-1400, and this 
conversion-factor rule does not constitute a significant change to the 
requirement. Public reporting burden for the certification is estimated 
to average 30 hours per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply

[[Page 59790]]

with, a collection of information subject to the requirements of the 
PRA, unless that collection of information displays a currently valid 
OMB Control Number.
D. Review Under the National Environmental Policy Act of 1969
    In this proposed rule, DOE proposes conversion factors to convert 
results from prior efficiency and delivery capacity metrics (and 
related energy conservation standard requirements) for consumer and 
certain commercial water heaters to the uniform efficiency descriptor. 
DOE has determined that this rule falls into a class of actions that 
are categorically excluded from review under the National Environmental 
Policy Act of 1969 (42 U.S.C. 4321 et seq.) and DOE's implementing 
regulations at 10 CFR part 1021. Specifically, this proposed rule would 
amend the existing rule without affecting the amount, quality, or 
distribution of energy usage, and, therefore, would not result in any 
environmental impacts. Thus, this rulemaking is covered by Categorical 
Exclusion A5 under 10 CFR part 1021, subpart D, which applies to any 
rulemaking that interprets or amends an existing rule without changing 
the environmental effect of that rule. Accordingly, neither an 
environmental assessment nor an environmental impact statement is 
required.
E. Review Under Executive Order 13132
    Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 10, 
1999) imposes certain requirements on agencies formulating and 
implementing policies or regulations that preempt State law or that 
have Federalism implications. The Executive Order requires agencies to 
examine the constitutional and statutory authority supporting any 
action that would limit the policymaking discretion of the States and 
to carefully assess the necessity for such actions. The Executive Order 
also requires agencies to have an accountable process to ensure 
meaningful and timely input by State and local officials in the 
development of regulatory policies that have Federalism implications. 
On March 14, 2000, DOE published a statement of policy describing the 
intergovernmental consultation process it will follow in the 
development of such regulations. 65 FR 13735. DOE has examined this 
proposed rule and has determined that it would not have a substantial 
direct effect on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. EPCA governs 
and prescribes Federal preemption of State regulations as to energy 
conservation for the products that are the subject of this proposed 
rule. States can petition DOE for exemption from such preemption to the 
extent, and based on criteria, set forth in EPCA. (42 U.S.C. 6297(d)) 
No further action is required by Executive Order 13132.
F. Review Under Executive Order 12988
    Regarding the review of existing regulations and the promulgation 
of new regulations, section 3(a) of Executive Order 12988, ``Civil 
Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal 
agencies the general duty to adhere to the following requirements: (1) 
Eliminate drafting errors and ambiguity; (2) write regulations to 
minimize litigation; (3) provide a clear legal standard for affected 
conduct rather than a general standard; and (4) promote simplification 
and burden reduction. Regarding the review required by section 3(a), 
section 3(b) of Executive Order 12988 specifically requires that 
Executive agencies make every reasonable effort to ensure that the 
regulation: (1) clearly specifies the preemptive effect, if any; (2) 
clearly specifies any effect on existing Federal law or regulation; (3) 
provides a clear legal standard for affected conduct while promoting 
simplification and burden reduction; (4) specifies the retroactive 
effect, if any; (5) adequately defines key terms; and (6) addresses 
other important issues affecting clarity and general draftsmanship 
under any guidelines issued by the Attorney General. Section 3(c) of 
Executive Order 12988 requires Executive agencies to review regulations 
in light of applicable standards in sections 3(a) and 3(b) to determine 
whether they are met or it is unreasonable to meet one or more of them. 
DOE has completed the required review and determined that, to the 
extent permitted by law, the proposed rule meets the relevant standards 
of Executive Order 12988.
G. Review Under the Unfunded Mandates Reform Act of 1995
    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
For a proposed regulatory action likely to result in a rule that may 
cause the expenditure by State, local, and Tribal governments, in the 
aggregate, or by the private sector of $100 million or more in any one 
year (adjusted annually for inflation), section 202 of UMRA requires a 
Federal agency to publish a written statement that estimates the 
resulting costs, benefits, and other effects on the national economy. 
(2 U.S.C. 1532(a), (b)) The UMRA also requires a Federal agency to 
develop an effective process to permit timely input by elected officers 
of State, local, and Tribal governments on a proposed ``significant 
intergovernmental mandate,'' and requires an agency plan for giving 
notice and opportunity for timely input to potentially affected small 
governments before establishing any requirements that might 
significantly or uniquely affect them. On March 18, 1997, DOE published 
a statement of policy on its process for intergovernmental consultation 
under UMRA. 62 FR 12820. (This policy is also available at http://energy.gov/gc/office-general-counsel.) DOE examined this proposed rule 
according to UMRA and its statement of policy and determined that the 
rule contains neither an intergovernmental mandate, nor a mandate that 
may result in the expenditure by State, local, and Tribal governments, 
in the aggregate, or by the private sector, of $100 million or more in 
any year. Accordingly, no further assessment or analysis is required 
under UMRA.
H. Review Under the Treasury and General Government Appropriations Act, 
1999
    Section 654 of the Treasury and General Government Appropriations 
Act, 1999 (Public Law 105-277) requires Federal agencies to issue a 
Family Policymaking Assessment for any rule that may affect family 
well-being. This rule would not have any impact on the autonomy or 
integrity of the family as an institution. Accordingly, DOE has 
concluded that it is not necessary to prepare a Family Policymaking 
Assessment.
I. Review Under Executive Order 12630
    Pursuant to Executive Order 12630, ``Governmental Actions and 
Interference with Constitutionally Protected Property Rights,'' 53 FR 
8859 (March 18, 1988), DOE has determined that this regulation would 
not result in any takings that might require compensation under the 
Fifth Amendment to the U.S. Constitution.
J. Review Under Treasury and General Government Appropriations Act, 
2001
    Section 515 of the Treasury and General Government Appropriations 
Act, 2001 (44 U.S.C. 3516 note) provides for agencies to review most 
disseminations of information to the

[[Page 59791]]

public under information quality guidelines established by each agency 
pursuant to general guidelines issued by OMB. OMB's guidelines were 
published at 67 FR 8452 (Feb. 22, 2002), and DOE's guidelines were 
published at 67 FR 62446 (Oct. 7, 2002). DOE has reviewed this proposed 
rule under the OMB and DOE guidelines and has concluded that it is 
consistent with applicable policies in those guidelines.
K. Review Under Executive Order 13211
    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355 
(May 22, 2001), requires Federal agencies to prepare and submit to OIRA 
at OMB, a Statement of Energy Effects for any proposed significant 
energy action. A ``significant energy action'' is defined as any action 
by an agency that promulgates or is expected to lead to promulgation of 
a final rule, and that: (1) Is a significant regulatory action under 
Executive Order 12866, or any successor order; and (2) is likely to 
have a significant adverse effect on the supply, distribution, or use 
of energy; or (3) is designated by the Administrator of OIRA as a 
significant energy action. For any proposed significant energy action, 
the agency must give a detailed statement of any adverse effects on 
energy supply, distribution, or use should the proposal be implemented, 
and of reasonable alternatives to the action and their expected 
benefits on energy supply, distribution, and use.
    This regulatory action, which would develop a conversion factor to 
amend the energy conservation standards for consumer and certain 
commercial water heaters in light of new test procedures is not a 
significant regulatory action under Executive Order 12866 or any 
successor order. Moreover, it would not have a significant adverse 
effect on the supply, distribution, or use of energy, nor has it been 
designated as a significant energy action by the Administrator of OIRA. 
Therefore, it is not a significant energy action, and, accordingly, DOE 
has not prepared a Statement of Energy Effects for this rulemaking.
L. Review Under Section 32 of the Federal Energy Administration Act of 
1974
    Under section 301 of the Department of Energy Organization Act 
(Pub. L. 95-91; 42 U.S.C. 7101 et seq.), DOE must comply with all laws 
applicable to the former Federal Energy Administration, including 
section 32 of the Federal Energy Administration Act of 1974 (Public Law 
93-275), as amended by the Federal Energy Administration Authorization 
Act of 1977 (Public Law 95-70). (15 U.S.C. 788; FEAA) Section 32 
essentially provides in relevant part that, where a proposed rule 
authorizes or requires use of commercial standards, the notice of 
proposed rulemaking must inform the public of the use and background of 
such standards. In addition, section 32(c) requires DOE to consult with 
the Attorney General and the Chairman of the Federal Trade Commission 
(FTC) concerning the impact of the commercial or industry standards on 
competition.
    This proposed rule to implement conversion factors between the 
existing water heaters test procedure and the amended test procedure 
does not incorporate testing methods contained in commercial standards.

V. Public Participation

A. Submission of Comments

    DOE will accept comments, data, and information regarding this 
supplemental proposed rule, no later than the date provided in the 
DATES section at the beginning of this SNOPR. Interested parties may 
submit comments, data, and other information using any of the methods 
described in the ADDRESSES section at the beginning of this document.
    Submitting comments via www.regulations.gov. The 
www.regulations.gov Web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
publicly viewable except for your first and last names, organization 
name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, DOE may not be able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment itself or in any documents attached to your 
comment. Any information that you do not want to be publicly viewable 
should not be included in your comment, nor in any document attached to 
your comment. Otherwise, persons viewing comments will see only first 
and last names, organization names, correspondence containing comments, 
and any documents submitted with the comments.
    Do not submit to www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (CBI)). Comments submitted through 
www.regulations.gov cannot be claimed as CBI. Comments received through 
the Web site will waive any CBI claims for the information submitted. 
For information on submitting CBI, see the Confidential Business 
Information section.
    DOE processes submissions made through www.regulations.gov before 
posting. Normally, comments will be posted within a few days of being 
submitted. However, if large volumes of comments are being processed 
simultaneously, your comment may not be viewable for up to several 
weeks. Please keep the comment tracking number that www.regulations.gov 
provides after you have successfully uploaded your comment.
    Submitting comments via email, hand delivery/courier, or mail. 
Comments and documents submitted via email, hand delivery/courier, or 
mail also will be posted to www.regulations.gov. If you do not want 
your personal contact information to be publicly viewable, do not 
include it in your comment or any accompanying documents. Instead, 
provide your contact information in a cover letter. Include your first 
and last names, email address, telephone number, and optional mailing 
address. The cover letter will not be publicly viewable as long as it 
does not include any comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. If you submit via mail or hand 
delivery/courier, please provide all items on a CD, if feasible, in 
which case it is not necessary to submit printed copies. No 
telefacsimiles (faxes) will be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, WordPerfect, or text (ASCII) file format. Provide documents that 
are not secured, that are written in English, and that are free of any 
defects or viruses. Documents should not contain special characters or 
any form of encryption and, if possible, they should carry the 
electronic signature of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This

[[Page 59792]]

reduces comment processing and posting time.
    Confidential Business Information. Pursuant to 10 CFR 1004.11, any 
person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit via 
email, postal mail, or hand delivery/courier two well-marked copies: 
one copy of the document marked ``confidential'' including all the 
information believed to be confidential, and one copy of the document 
marked ``non-confidential'' with the information believed to be 
confidential deleted. Submit these documents via email or on a CD, if 
feasible. DOE will make its own determination about the confidential 
status of the information and treat it according to its determination.
    Factors of interest to DOE when evaluating requests to treat 
submitted information as confidential include: (1) A description of the 
items; (2) whether and why such items are customarily treated as 
confidential within the industry; (3) whether the information is 
generally known by or available from other sources; (4) whether the 
information has previously been made available to others without 
obligation concerning its confidentiality; (5) an explanation of the 
competitive injury to the submitting person which would result from 
public disclosure; (6) when such information might lose its 
confidential character due to the passage of time; and (7) why 
disclosure of the information would be contrary to the public interest.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).

B. Issues on Which DOE Seeks Comment

    Although DOE welcomes comments on any aspect of this proposal, DOE 
is particularly interested in receiving comments and views of 
interested parties concerning the following issues:
    1. Is DOE's method of applying the regression for electric storage 
water heaters with storage volumes at or below 55 gallons in developing 
the conversion equation for grid-enabled water heaters appropriate?
    2. Is DOE's use of the standard and low-NOX conversion 
to calculate the energy conservation standard for consumer gas-fired 
storage water heaters less than or equal to 55 gallons, and its 
tentative decision not to propose separate standards for ultra-low-
NOX gas-fired storage water heaters appropriate?
    3. Are DOE's assumptions for the typical input rating and recovery 
efficiency of consumer gas-fired storage water heaters above 55 gallons 
appropriate?
    4. Is DOE's approach for estimating the recovery efficiency of a 
minimally-compliant (i.e., 0.93 EF) electric instantaneous water heater 
appropriate?

VI. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this 
supplemental notice of proposed rulemaking.

List of Subjects

10 CFR Part 429

    Confidential business information, Energy conservation, Household 
appliances, Imports, Reporting and recordkeeping requirements.

10 CFR Part 430

    Administrative practice and procedure, Confidential business 
information, Energy conservation, Household appliances, Imports, 
Incorporation by reference, Intergovernmental relations, Small 
businesses.

10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Test procedures, Incorporation by reference, Reporting and 
recordkeeping requirements.

    Issued in Washington, DC, on August 15, 2016.
Kathleen B. Hogan,
Deputy Assistant Secretary for Energy Efficiency, Energy Efficiency and 
Renewable Energy.

    For the reasons stated in the preamble, DOE proposes to amend parts 
429, 430, and 431 of chapter II subchapter D of Title 10, Code of 
Federal Regulations as set forth below:

PART 429--CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER 
PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT

0
1. The authority citation for part 429 continues to read as follows:

    Authority:  42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.

0
2. Section 429.17 is revised to read as follows:


Sec.  429.17  Water heaters.

    (a) Determination of represented value.
    (1) As of July 13, 2015, manufacturers must determine the 
represented value for each new basic model of water heater by applying 
an AEDM in accordance with 10 CFR 429.70 or by testing for the uniform 
energy factor, in conjunction with the applicable sampling provisions 
as follows:
    (i) If the represented value is determined through testing, the 
general requirements of 10 CFR 429.11 are applicable; and
    (ii) For each basic model selected for testing, a sample of 
sufficient size shall be randomly selected and tested to ensure that--
    (A) Any represented value of the energy consumption or other 
measure of energy use of a basic model for which consumers would favor 
lower values shall be greater than or equal to the higher of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.039
    

and, x is the sample mean; n is the number of samples; and 
xi is the i\th\ sample;
    Or,
    (2) The upper 95-percent confidence limit (UCL) of the true mean 
divided by 1.10, where
[GRAPHIC] [TIFF OMITTED] TP30AU16.040


[[Page 59793]]


    And x is the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    (B) Any represented value of energy efficiency or other measure of 
energy consumption of a basic model for which consumers would favor 
higher values shall be less than or equal to the lower of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.041
    

and, x is the sample mean; n is the number of samples; and x 
i is the i \th\ sample;
    Or,
    (2) The lower 95-percent confidence limit (LCL) of the true mean 
divided by 0.90, where:
[GRAPHIC] [TIFF OMITTED] TP30AU16.042

    And x is the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    (C) Any represented value of the rated storage volume must be equal 
to the mean of the measured storage volumes of all the units within the 
sample.
    (D) Any represented value of first-hour rating or maximum gallons 
per minute (GPM) must be equal to the mean of the measured first-hour 
ratings or measured maximum GPM ratings, respectively, of all the units 
within the sample.
    (2) For basic models initially certified before July 13, 2015 
(using either the energy factor test procedure contained in appendix E 
to subpart B of 10 CFR part 430 of the January 1, 2015 edition of the 
Code of Federal Regulations or the thermal efficiency and standby loss 
test procedures contained in 10 CFR 431.106 of the January 1, 2015 
edition of the Code of Federal Regulations, in conjunction with 
applicable sampling provisions), manufacturers must:
    (i) Determine the represented value for each basic model by 
applying an AEDM in accordance with 10 CFR 429.70 or by testing for the 
uniform energy factor, in conjunction with the applicable sampling 
provisions of paragraph (a)(1); or
    (ii) Calculate the uniform energy factor for each test sample by 
applying the following mathematical conversion factors to test data 
previously obtained through testing according to appendix E to subpart 
B of 10 CFR part 430 of the January 1, 2015 edition of the Code of 
Federal Regulations or the thermal efficiency and standby loss test 
procedures contained in 10 CFR 431.106 of the January 1, 2015 edition 
of the Code of Federal Regulations. Represented values of uniform 
energy factor, first-hour rating, and maximum GPM rating based on a 
calculation using this mathematical conversion factor must be 
determined using the applicable sampling provisions in paragraphs 
(a)(1)(i) and (a)(1)(ii) of this section.
    (A) The applicable mathematical conversion factors are as follows:

------------------------------------------------------------------------
                                    Distinguishing     Conversion factor
          Product class                criteria                *
------------------------------------------------------------------------
Consumer Gas-fired Water Heater.  Non-Condensing,     New FHR = 7.9592 +
                                   Standard and Low    0.8752 x FHRP.
                                   NOX.               New UEF = -0.0002
                                                       + 0.9858 x
                                                       UEFWHAM.
                                  Non-Condensing,     New FHR = 25.0680
                                   Ultra-Low NOX.      + 0.6535 x FHRP.
                                                      New UEF = 0.0746 +
                                                       0.8653 x UEFWHAM.
                                  Condensing........  New FHR = 1.0570 x
                                                       FHRP.
                                                      New UEF = 0.4242 +
                                                       0.4641 x UEFWHAM.
Consumer Oil-fired Water Heater.  N/A...............  New FHR = 1.1012 x
                                                       FHRP.
                                                      New UEF = -0.0934
                                                       + 1.1144 x
                                                       UEFWHAM.
Consumer Electric Water Heater..  Electric            New FHR = 9.2827 +
                                   Resistance.         0.8092 x FHRP.
                                                      New UEF = 0.4774 +
                                                       0.4740 x UEFWHAM.
                                  Heat Pump.........  New FHR = -4.2705
                                                       + 0.9947 x FHRP.
                                                      New UEF = 0.1513 +
                                                       0.8407 x EF +
                                                       0.0043 x DV.
Tabletop Water Heater...........  N/A...............  New FHR = 41.5127
                                                       + 0.1989 x FHRP.
                                                      New UEF = -0.3305
                                                       + 1.3983 x
                                                       UEFWHAM.
Instantaneous Gas-fired Water     N/A...............  New Max GPM =
 Heater.                                               1.1461 x Max
                                                       GPMP.
                                                      New UEF = 0.1006 +
                                                       0.8622 x
                                                       UEFmodel.
Instantaneous Electric Water      N/A...............  New Max GPM =
 Heater.                                               1.1461 x Max
                                                       GPMP.
                                                      New UEF = 0.9847 x
                                                       UEFmodel.
Grid-Enabled Water Heater.......  N/A...............  New FHR = 9.2827 +
                                                       0.8092 x FHRP.
                                                      New UEF = 0.4774 +
                                                       0.4740 x UEFWHAM.
Residential-Duty Commercial Gas-  N/A...............  New FHR = -35.8233
 fired Water Heater.                                   + 0.4649 x Vr +
                                                       160.5089 x Et.
                                                      New UEF = -0.0022
                                                       + 1.0002 x UEFrd.
Residential-Duty Commercial Oil-  N/A...............  New FHR = -35.8233
 fired Water Heater.                                   + 0.4649 x Vr +
                                                       160.5089 x Et.
                                                      New UEF = -0.0022
                                                       + 1.0002 x UEFrd.

[[Page 59794]]

 
Residential-Duty Commercial       N/A...............  New Max GPM =
 Electric Instantaneous Water                          0.0146 + 0.0295 x
 Heater.                                               Q.
                                                      New UEF = UEFrd,
                                                       model.
------------------------------------------------------------------------
* FHRP = prior first-hour rating.
Max GPMP = prior max GPM rating.
Q = nameplate input rate, in kBtu/h.
Et = thermal efficiency rating.
UEFWHAM = the UEF predicted based on the WHAM equation for consumer
  storage water heaters, as defined in paragraph (a)(2)(ii)(B) of this
  section.
UEFrd = the modified WHAM for residential-duty commercial water heaters,
  as defined in paragraph (a)(2)(ii)(B) of this section.
UEFmodel = the UEF predicted based on the analytical model developed by
  DOE for consumer instantaneous water heaters, as defined in paragraph
  (a)(2)(ii)(B) of this section.
UEFrd model = the UEF predicted based on the analytical model developed
  by DOE for residential-duty commercial instantaneous water heaters, as
  defined in paragraph (a)(2)(ii)(B) of this section.
DV = drawn volume of water in UEF simulated-use test.
Vr = rated storage volume in gallons.

    (B) Calculate UEFWHAM (for consumer storage water 
heaters), UEFmodel (for consumer instantaneous water 
heaters), UEFrd (for residential-duty commercial storage 
water heaters), and UEFrd, model (for residential-duty 
commercial electric instantaneous water heaters) as follows:
    (1) For consumer storage water heaters:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.043
    
    Where a, b, c, and d are coefficients based on the applicable draw 
pattern as specified in the table below; EF is the energy factor; 
[eta]r is the recovery efficiency in decimal form; and P is 
the input rate in Btu/h.

----------------------------------------------------------------------------------------------------------------
                  Draw pattern                           a               b               c               d
----------------------------------------------------------------------------------------------------------------
Very Small......................................        0.250266            57.5        0.039864            67.5
Low.............................................        0.065860            57.5        0.039864            67.5
Medium..........................................        0.045503            57.5        0.039864            67.5
High............................................        0.029794            57.5        0.039864            67.5
----------------------------------------------------------------------------------------------------------------

    (2) For consumer instantaneous water heaters:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.044
    
    Where [eta]r is the recovery efficiency expressed in 
decimal form and A is dependent upon the applicable draw pattern and 
fuel type as specified in the table below.

------------------------------------------------------------------------
                                                            A
                 Draw pattern                  -------------------------
                                                  Electric       Gas
------------------------------------------------------------------------
Very Small....................................     0.003819     0.026915
Low...........................................     0.001549     0.010917
Medium........................................     0.001186     0.008362
High..........................................     0.000785     0.005534
------------------------------------------------------------------------

    (3) For residential-duty commercial storage water heaters:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.045
    
    Where P is the input rate in Btu/h; Et is the thermal efficiency; 
SL is the standby loss in Btu/h; and F and G are coefficients as 
specified in the table below based on the applicable draw pattern.

------------------------------------------------------------------------
                 Draw pattern                        F            G
------------------------------------------------------------------------
Very Small....................................     0.821429    0.0043520
Low...........................................     0.821429    0.0011450
Medium........................................     0.821429    0.0007914
High..........................................     0.821429    0.0005181
------------------------------------------------------------------------

    (4) For residential-duty commercial electric instantaneous water 
heaters:

[[Page 59795]]

[GRAPHIC] [TIFF OMITTED] TP30AU16.046

    Where Et is the thermal efficiency expressed in decimal 
form and A is dependent upon the applicable draw pattern, as specified 
in the table below.

------------------------------------------------------------------------
                        Draw pattern                              A
------------------------------------------------------------------------
Very Small.................................................     0.003819
Low........................................................     0.001549
Medium.....................................................     0.001186
High.......................................................     0.000785
------------------------------------------------------------------------

    (b) Certification reports.
    (1) The requirements of 10 CFR 429.12 apply; and
    (2) Pursuant to 10 CFR 429.12(b)(13), a certification report must 
include the following public product-specific information:
    (i) For storage-type water heater basic models previously certified 
for energy factor pursuant to Sec.  429.17(a) of the January 1, 2015 
edition of the Code of Federal Regulations, and for which uniform 
energy factor is calculated pursuant to 10 CFR 429.17(a)(2)(ii): The 
energy factor (EF, rounded to the nearest 0.01), the uniform energy 
factor (UEF, rounded to the nearest 0.01), the rated storage volume in 
gallons (gal, rounded to the nearest 1 gal), the uniform energy factor 
test procedure first-hour rating in gallons (gal, rounded to the 
nearest 1 gal) as determined under paragraph (a)(2)(ii)(A) of this 
section, the previously certified first-hour rating under the energy 
factor test procedure in gallons (gal, rounded to the nearest 1 gal), 
and the recovery efficiency in percent (%, rounded to the nearest 1%);
    (ii) For storage-type water heater basic models rated pursuant to 
10 CFR 429.17(a)(1) or 10 CFR 429.17(a)(2)(i): The uniform energy 
factor (UEF, rounded to the nearest 0.01), the rated storage volume in 
gallons (gal, rounded to the nearest 1 gal), the first-hour rating in 
gallons (gal, rounded to the nearest 1 gal), and the recovery 
efficiency in percent (%, rounded to the nearest 1%);
    (iii) For instantaneous-type water heater basic models previously 
certified for energy factor pursuant to Sec.  429.17(a) of the January 
1, 2015 edition of the Code of Federal Regulations, and for which 
uniform energy factor is calculated pursuant to 10 CFR 
429.17(a)(2)(ii): The energy factor (EF, rounded to the nearest 0.01), 
the uniform energy factor (UEF. rounded to the nearest 0.01), the rated 
storage volume in gallons (gal, rounded to the nearest 1 gal), the 
uniform energy factor test procedure maximum gallons per minute (gpm, 
rounded to the nearest 0.1 gpm) as determined under-paragraph 
(a)(2)(ii)(A) of this section, the previously certified maximum gallons 
per minute (gpm, rounded to the nearest 0.1 gpm) under the energy 
factor test procedure, and the recovery efficiency in percent (%, 
rounded to the nearest 1%); and
    (iv) For instantaneous-type water heater basic models rated 
pursuant to 10 CFR 429.17(a)(1) or 10 CFR 429.17(a)(2)(i): The uniform 
energy factor (UEF, rounded to the nearest 0.01), the rated storage 
volume in gallons (gal, rounded to the nearest 1 gal), the maximum 
gallons per minute (gpm, rounded to the nearest 0.1 gpm), and the 
recovery efficiency in percent (%, rounded to the nearest 1%).(the 
uniform energy factor test procedure first-hour rating in gallons (gal, 
rounded to the nearest 1 gal) as determined under paragraph 
(a)(2)(ii)(A) of this section,
    (v) For grid-enabled water heater basic models rated pursuant to 10 
CFR 429.17(a)(1) or 10 CFR 429.17(a)(2)(i): The uniform energy factor 
(UEF, rounded to the nearest 0.01), the rated storage volume in gallons 
(gal, rounded to the nearest 1 gal), the first-hour rating in gallons 
(gal, rounded to the nearest 1 gal), and the recovery efficiency in 
percent (%, rounded to the nearest 1%), a declaration that the model is 
a grid-enabled water heater, whether it is equipped at the point of 
manufacture with an activation lock, and whether it bears a permanent 
label applied by the manufacturer that advises purchasers and end-users 
of the intended and appropriate use of the product.
    3. Section 429.17 is further revised, proposed to be effective 
(date one year after publication of test procedure final rule), to read 
as follows:


Sec.  429.17  Water heaters.

    (a) Determination of represented value.
    (1) Manufacturers must determine the represented value for each 
water heater by applying an AEDM in accordance with 10 CFR 429.70 or by 
testing for the uniform energy factor, in conjunction with the 
applicable sampling provisions as follows:
    (i) If the represented value is determined through testing, the 
general requirements of 10 CFR 429.11 are applicable; and
    (ii) For each basic model selected for testing, a sample of 
sufficient size shall be randomly selected and tested to ensure that--
    (A) Any represented value of the estimated annual operating cost or 
other measure of energy consumption of a basic model for which 
consumers would favor lower values shall be greater than or equal to 
the higher of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.047
    
    and, x is the sample mean; n is the number of samples; and 
xi is the i\th\ sample;
    Or,
    (2) The upper 95-percent confidence limit (UCL) of the true mean 
divided by 1.10, where:
[GRAPHIC] [TIFF OMITTED] TP30AU16.048

    And x is the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    (B) Any represented value of the uniform energy factor, or other 
measure of energy consumption of a basic model for which consumers 
would favor higher values shall be less than or equal to the lower of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP30AU16.049
    
    and, x is the sample mean; n is the number of samples; and 
xi is the i\th\ sample;
    Or,
    (2) The lower 95-percent confidence limit (LCL) of the true mean 
divided by 0.90, where:
[GRAPHIC] [TIFF OMITTED] TP30AU16.050

    And x is the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    (C) Any represented value of the rated storage volume must be equal 
to the mean of the measured storage volumes of all the units within the 
sample.
    (D) Any represented value of first-hour rating or maximum gallons 
per

[[Page 59796]]

minute (GPM) must be equal to the mean of the measured first-hour 
ratings or measured maximum GPM ratings, respectively, of all the units 
within the sample.
    (b) Certification reports.
    (1) The requirements of 10 CFR 429.12 are applicable to water 
heaters; and
    (2) Pursuant to 10 CFR 429.12(b)(13), a certification report shall 
include the following public product-specific information:
    (i) For storage-type water heater basic models: The uniform energy 
factor (UEF, rounded to the nearest 0.01), the rated storage volume in 
gallons (rounded to the nearest 1 gal), the first-hour rating in 
gallons (gal, rounded to the nearest 1 gal), the recovery efficiency in 
percent (%, rounded to the nearest 1%);
    (ii) For instantaneous-type water heater basic models: The uniform 
energy factor (UEF, rounded to the nearest 0.01), the rated storage 
volume in gallons (gal, rounded to the nearest 1 gal), the maximum 
gallons per minute (gpm, rounded to the nearest 0.1 gpm), the recovery 
efficiency in percent (%, rounded to the nearest 1%); and
    (iii) For grid-enabled water heater basic models: The uniform 
energy factor (UEF, rounded to the nearest 0.01), the rated storage 
volume in gallons (gal, rounded to the nearest 1 gal), the first-hour 
rating in gallons (gal, rounded to the nearest 1 gal), the recovery 
efficiency in percent (%, rounded to the nearest 1%), a declaration 
that the model is a grid-enabled water heater, whether it is equipped 
at the point of manufacture with an activation lock, and whether it 
bears a permanent label applied by the manufacturer that advises 
purchasers and end-users of the intended and appropriate use of the 
product.
0
4. Section 429.44 is amended by revising paragraph (d) [proposed at 81 
FR 28588, 28636 (May 9, 2016)] to read as follows:


Sec.  429.44  Commercial water heating equipment.

* * * * *
    (d) Certification reports for residential-duty commercial water 
heaters.
    (1) The requirements of Sec.  429.12 apply; and
    (2) Pursuant to Sec.  429.12(b)(13), a certification report must 
include the following public equipment-specific information:
    (i) Residential-duty commercial gas-fired and oil-fired storage 
water heaters previously certified for thermal efficiency and standby 
loss pursuant to 10 CFR 429.44(b) of the January 1, 2015 edition of the 
Code of Federal Regulations, and for which uniform energy factor is 
calculated pursuant to 10 CFR 429.17(a)(2)(ii): The thermal efficiency 
in percent (%), the standby loss in British thermal units per hour 
(Btu/h), the uniform energy factor (UEF, rounded to the nearest 0.01), 
the rated storage volume in gallons (gal), and the nameplate input rate 
in Btu/h.
    (ii) Residential-duty commercial gas-fired and oil-fired storage 
water heaters rated for uniform energy factor pursuant to 10 CFR 
429.17(a)(2)(i): The uniform energy factor (UEF, rounded to the nearest 
0.01), the rated storage volume in gallons (rounded to the nearest 1 
gal), the first-hour rating in gallons (gal, rounded to the nearest 1 
gal), and the recovery efficiency in percent (%, rounded to the nearest 
1%).
    (iii) Residential-duty commercial electric instantaneous water 
heaters previously certified for thermal efficiency and standby loss 
pursuant to 10 CFR 429.44(b) of the January 1, 2015 edition of the Code 
of Federal Regulations, and for which uniform energy factor is 
calculated pursuant to 10 CFR 429.17(a)(2)(ii): The thermal efficiency 
in percent (%), the standby loss in British thermal units per hour 
(Btu/h), the uniform energy factor (UEF, rounded to the nearest 0.01), 
the rated storage volume in gallons (gal), and the nameplate input rate 
in kilowatts (kW).
    (iv) Residential-duty commercial electric instantaneous water 
heaters rated for uniform energy factor pursuant to 10 CFR 
429.17(a)(2)(i): The uniform energy factor (UEF, rounded to the nearest 
0.01), the rated storage volume in gallons (gal, rounded to the nearest 
1 gal), the maximum gallons per minute (gpm, rounded to the nearest 0.1 
gpm), and the recovery efficiency in percent (%, rounded to the nearest 
1%)).
* * * * *
0
5. Section 429.44 is further amended, proposed to be effective (date 
one year after publication of test procedure final rule), by revising 
paragraph (d)(2) to read as follows:


Sec.  429.44  Commercial water heating equipment.

* * * * *
    (d) * * *
    (2) Pursuant to Sec.  429.12(b)(13), a certification report for 
equipment must include the following public equipment-specific 
information:
    (i) Residential-duty commercial gas-fired and oil-fired storage 
water heaters: The uniform energy factor (UEF, rounded to the nearest 
0.01), the rated storage volume in gallons (gal, rounded to the nearest 
1 gal), the first-hour rating in gallons (gal, rounded to the nearest 1 
gal), and the recovery efficiency in percent (%, rounded to the nearest 
1%).
    (ii) Residential-duty commercial electric instantaneous water 
heaters: The uniform energy factor (UEF, rounded to the nearest 0.01), 
the rated storage volume in gallons (gal, rounded to the nearest 1 
gal), the maximum gallons per minute (gpm, rounded to the nearest 0.1 
gpm), and the recovery efficiency in percent (%, rounded to the nearest 
1%).
* * * * *
0
6. Section 429.134 is revised by amending paragraph (d)(2) to read as 
follows:


Sec.  429.134  Product-specific enforcement provisions.

* * * * *
    (d) * * *
    (2) Verification of rated storage volume. The storage volume of the 
basic model will be measured pursuant to the test requirements of 
appendix E to subpart B of 10 CFR part 430 for each unit tested. The 
mean of the measured values will be compared to the rated storage 
volume as certified by the manufacturer. The rated value will be 
considered valid only if the measurement is within two percent of the 
certified rating.
    (i) If the rated storage volume is found to be within 2 percent of 
the mean of the measured value of storage volume, then the rated value 
will be used as the basis for calculation of the required uniform 
energy factor for the basic model.
    (ii) If the rated storage volume is found to vary more than 2 
percent from the mean of the measured values, then the mean of the 
measured values will be used as the basis for calculation of the 
required uniform energy factor for the basic model.
* * * * *

PART 430--ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS

0
7. The authority citation for part 430 continues to read as follows:

    Authority: 42 U.S.C. 6291-6309; 28 U.S.C. 2461 note.

0
8. Section 430.23 is amended by revising paragraph (e) to read as 
follows:


Sec.  430.23  Test procedures for the measurement of energy and water 
consumption.

* * * * *
    (e) Water Heaters.
    (1) For water heaters tested using energy factor:
    (i) The estimated annual operating cost for water heaters tested in 
terms of energy factor is calculated as--

[[Page 59797]]

    (A) For a gas-fired or oil-fired water heater, the product of the 
annual energy consumption, determined according to section 6.1.8 or 
6.2.5 of appendix E to subpart B of 10 CFR part 430 of the January 1, 
2015 edition of the Code of Federal Regulations, times the 
representative average unit cost of gas or oil, as appropriate, in 
dollars per Btu as provided by the Secretary. Round the resulting 
product to the nearest dollar per year.
    (B) For an electric water heater, the product of the annual energy 
consumption, determined according to section 6.1.8 or 6.2.5 of appendix 
E to subpart B to 10 CFR part 430 of the January 1, 2015 edition of the 
Code of Federal Regulations, times the representative average unit cost 
of electricity in dollars per kilowatt-hour as provided by the 
Secretary, divided by 3412 Btu per kilowatt-hour. Round the resulting 
quotient to the nearest dollar per year.
    (ii) For an individual unit, determine the tested energy factor in 
accordance with section 6.1.7 or 6.2.4 of appendix E to subpart B of 10 
CFR part 430 of the January 1, 2015 edition of the Code of Federal 
Regulations, and round the value to the nearest 0.01.
    (2) For water heaters tested using uniform energy factor:
    (i) The estimated annual operating cost is calculated as:
    (A) For a gas-fired or oil-fired water heater, the sum of: The 
product of the annual gas or oil energy consumption, determined 
according to section 6.3.9 or 6.4.6 of appendix E of this subpart, 
times the representative average unit cost of gas or oil, as 
appropriate, in dollars per Btu as provided by the Secretary; plus the 
product of the annual electric energy consumption, determined according 
to section 6.3.8 or 6.4.5 of appendix E of this subpart, times the 
representative average unit cost of electricity in dollars per 
kilowatt-hour as provided by the Secretary. Round the resulting sum to 
the nearest dollar per year.
    (B) For an electric water heater, the product of the annual energy 
consumption, determined according to section 6.3.7 or 6.4.4 of appendix 
E of this subpart, times the representative average unit cost of 
electricity in dollars per kilowatt-hour as provided by the Secretary. 
Round the resulting product to the nearest dollar per year.
    (ii) For an individual unit, determine the tested uniform energy 
factor in accordance with section 6.3.6 or 6.4.3 of appendix E of this 
subpart, and round the value to the nearest 0.01.
* * * * *
0
9. Section 430.23 paragraph (e) is further revised, proposed to be 
effective (date one year after publication of test procedure final 
rule), to read as follows:


Sec.  430.23  Test procedures for the measurement of energy and water 
consumption.

* * * * *
    (e) Water Heaters.
    (1) The estimated annual operating cost is calculated as:
    (i) For a gas-fired or oil-fired water heater, the sum of: The 
product of the annual gas or oil energy consumption, determined 
according to section 6.3.9 or 6.4.6 of appendix E of this subpart, 
times the representative average unit cost of gas or oil, as 
appropriate, in dollars per Btu as provided by the Secretary; plus the 
product of the annual electric energy consumption, determined according 
to section 6.3.8 or 6.4.5 of appendix E of this subpart, times the 
representative average unit cost of electricity in dollars per 
kilowatt-hour as provided by the Secretary. Round the resulting sum to 
the nearest dollar per year.
    (ii) For an electric water heater, the product of the annual energy 
consumption, determined according to section 6.3.7 or 6.4.4 of appendix 
E of this subpart, times the representative average unit cost of 
electricity in dollars per kilowatt-hour as provided by the Secretary. 
Round the resulting product to the nearest dollar per year.
    (2) For an individual unit, determine the tested uniform energy 
factor in accordance with section 6.3.6 or 6.4.3 of appendix E of this 
subpart, and round the value to the nearest 0.01.
* * * * *
0
10. Section 430.32 is amended by revising paragraph (d) to read as 
follows:


Sec.  430.32  Energy and water conservation standards and their 
compliance dates.

* * * * *
    (d) Water heaters. The uniform energy factor of water heaters shall 
not be less than the following:

----------------------------------------------------------------------------------------------------------------
                                     Rated storage volume and
           Product class                 input rating  (if           Draw pattern        Uniform energy factor
                                            applicable)
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage Water Heater....  <20 gal...................  Very Small...........  0.2471-(0.0002 x Vr).
                                                                Low..................  0.5132-(0.0012 x Vr).
                                                                Medium...............  0.5827-(0.0015 x Vr).
                                                                High.................  0.6507-(0.0019 x Vr).
                                    >=20 gal and <=55 gal.....  Very Small...........  0.3456-(0.0020 x Vr).
                                                                Low..................  0.5982-(0.0019 x Vr).
                                                                Medium...............  0.6483-(0.0017 x Vr).
                                                                High.................  0.6920-(0.0013 x Vr).
                                    >55 gal and <=100 gal.....  Very Small...........  0.6470-(0.0006 x Vr).
                                                                Low..................  0.7689-(0.0005 x Vr).
                                                                Medium...............  0.7897-(0.0004 x Vr).
                                                                High.................  0.8072-(0.0003 x Vr).
                                    >100 gal..................  Very Small...........  0.1755-(0.0006 x Vr).
                                                                Low..................  0.4671-(0.0015 x Vr).
                                                                Medium...............  0.5719-(0.0018 x Vr).
                                                                High.................  0.6916-(0.0022 x Vr).
Oil-fired Storage Water Heater....  <=50 gal..................  Very Small...........  0.1822-(-0.0001 x Vr).
                                                                Low..................  0.5313-(0.0014 x Vr).
                                                                Medium...............  0.6316-(0.0020 x Vr).
                                                                High.................  0.7334-(0.0028 x Vr).
                                    >50 gal...................  Very Small...........  0.1068-(0.0007 x Vr).
                                                                Low..................  0.4190-(0.0017 x Vr).
                                                                Medium...............  0.5255-(0.0021 x Vr).
                                                                High.................  0.6438-(0.0025 x Vr).
Electric Storage Water Heaters....  <20 gal...................  Very Small...........  0.7836-(0.0013 x Vr).
                                                                Low..................  0.8939-(0.0008 x Vr).
                                                                Medium...............  0.9112-(0.0007 x Vr).
                                                                High.................  0.9255-(0.0006 x Vr).
                                    >=20 gal and <=55 gal.....  Very Small...........  0.8808-(0.0008 x Vr).
                                                                Low..................  0.9254-(0.0003 x Vr).

[[Page 59798]]

 
                                                                Medium...............  0.9307-(0.0002 x Vr).
                                                                High.................  0.9349-(0.0001 x Vr).
                                    >55 gal and <=120 gal.....  Very Small...........  1.9236-(0.0011 x Vr).
                                                                Low..................  2.0440-(0.0011 x Vr).
                                                                Medium...............  2.1171-(0.0011 x Vr).
                                                                High.................  2.2418-(0.0011 x Vr).
                                    >120 gal..................  Very Small...........  0.6802-(0.0003 x Vr).
                                                                Low..................  0.8620-(0.0006 x Vr).
                                                                Medium...............  0.9042-(0.0007 x Vr).
                                                                High.................  0.9437-(0.0007 x Vr).
Tabletop Water Heater.............  All.......................  Very Small...........  0.6323-(0.0058 x Vr).
                                                                Low..................  0.9188-(0.0031 x Vr).
                                                                Medium...............  0.9577-(0.0023 x Vr).
                                                                High.................  0.9884-(0.0016 x Vr).
Instantaneous Gas-fired Water       <2 gal and >50,000 Btu/h..  Very Small...........  0.7964-(0.0000 x Vr).
 Heater.
                                                                Low..................  0.8055-(0.0000 x Vr).
                                                                Medium...............  0.8070-(0.0000 x Vr).
                                                                High.................  0.8086-(0.0000 x Vr).
                                    >=2 gal or <=50,000 Btu/h.  Very Small...........  0.3013-(0.0023 x Vr).
                                                                Low..................  0.5421-(0.0024 x Vr).
                                                                Medium...............  0.5942-(0.0021 x Vr).
                                                                High.................  0.6415-(0.0017 x Vr).
Instantaneous Oil-fired Water       All.......................  Very Small...........  0.1430-(0.0015 x Vr).
 Heater.
                                                                Low..................  0.4455-(0.0023 x Vr).
                                                                Medium...............  0.5339-(0.0023 x Vr).
                                                                High.................  0.6245-(0.0021 x Vr).
Instantaneous Electric Water        All.......................  Very Small...........  0.9161-(0.0039 x Vr).
 Heater.
                                                                Low..................  0.9159-(0.0009 x Vr).
                                                                Medium...............  0.9160-(0.0005 x Vr).
                                                                High.................  0.9161-(0.0003 x Vr).
Grid-Enabled Water Heater.........  >75 gal...................  Very Small...........  1.0136-(0.0028 x Vr).
                                                                Low..................  0.9984-(0.0014 x Vr).
                                                                Medium...............  0.9853-(0.0010 x Vr).
                                                                High.................  0.9720-(0.0007 x Vr).
----------------------------------------------------------------------------------------------------------------
*Vr is the rated storage volume in gallons.

* * * * *

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
11. The authority citation for part 431 continues to read as follows:

    Authority:  42 U.S.C. 6291-6317. 28 U.S.C. 2461 note.

0
12. Section 431.110 is amended by revising paragraph (d) [proposed at 
81 FR 34440. 34536-34537 (May 31, 2016)] to read as follows:


Sec.  431.110  Energy conservation standards and their effective dates.

* * * * *
    (d) Each residential-duty commercial water heater manufactured 
prior to (date 3 years after publication in the Federal Register of the 
final rule establishing amended energy conservation standards for 
commercial water-heating equipment) must meet the applicable energy 
conservation standard level(s) as follows:

----------------------------------------------------------------------------------------------------------------
         Product class              Specifications \a\        Draw pattern         Uniform energy factor \b\
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage..............  >75 kBtu/hr and <=105     Very Small.......  0.2670 - (0.0009 x Vr)
                                  kBtu/hr and <=120 gal.
                                                           Low..............  0.5356 - (0.0012 x Vr)
                                                           Medium...........  0.5996 - (0.0011 x Vr)
                                                           High.............  0.6592 - (0.0009 x Vr)
Oil-fired Storage..............  >105 kBtu/hr and <=140    Very Small.......  0.2932 - (0.0015 x Vr)
                                  kBtu/hr and <=120 gal.
                                                           Low..............  0.5596 - (0.0018 x Vr)
                                                           Medium...........  0.6194 - (0.0016 x Vr)
                                                           High.............  0.6740 - (0.0013 x Vr)
Electric Instantaneous.........  >12 kW and <=58.6 kW and  Very Small.......  0.80
                                  <=2 gal.
                                                           Low..............  0.80
                                                           Medium...........  0.80
                                                           High.............  0.80
----------------------------------------------------------------------------------------------------------------
\a\ Additionally, to be classified as a residential-duty commercial water heater, a commercial water heater must
  meet the following conditions: (1) If the water heater requires electricity, it must use a single-phase
  external power supply; and (2) the water heater must not be designed to heat water to temperatures greater
  than 180 [deg]F.
\b\ Vr is the rated storage volume in gallons.

* * * * *
[FR Doc. 2016-20097 Filed 8-29-16; 8:45 am]
 BILLING CODE 6450-01-P